fix getErrorCode

[AsiiaPine]

Fixing the signed overflow caused by int to in16_t conversion in getErrorCode function

-- Configuring done (1.1s)
-- Generating done (0.0s)
-- Build files have been written to: /home/asiia/Documents/work/nodes/mini_v2_node/build/dronecan_sitl/obj
make[1]: Entering directory '/home/asiia/Documents/work/nodes/mini_v2_node/build/dronecan_sitl/obj'
[  3%] Building CXX object Src/platform/ubuntu/CMakeFiles/node.dir/__/__/__/Libs/libparams/platform_specific/ubuntu/flash_driver.cpp.o
[  6%] Building C object Src/platform/ubuntu/CMakeFiles/node.dir/__/__/__/Libs/Dronecan/platform_specific/socketcan/socketcan.c.o
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c: In function ‘getErrorCode’:
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
  180 | }
      | ^
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c: In function ‘socketcanInit’:
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c: In function ‘socketcanClose’:
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c: In function ‘socketcanTransmit’:
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c: In function ‘socketcanReceive’:
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
/home/asiia/Documents/work/nodes/mini_v2_node/Libs/Dronecan/platform_specific/socketcan/socketcan.c:180:1: error: assuming signed overflow does not occur when determining that expression is always non-negative [-Werror=strict-overflow]
cc1: all warnings being treated as errors
make[3]: *** [Src/platform/ubuntu/CMakeFiles/node.dir/build.make:149: Src/platform/ubuntu/CMakeFiles/node.dir/__/__/__/Libs/Dronecan/platform_specific/socketcan/socketcan.c.o] Error 1
make[2]: *** [CMakeFiles/Makefile2:106: Src/platform/ubuntu/CMakeFiles/node.dir/all] Error 2
make[1]: *** [Makefile:91: all] Error 2
make[1]: Leaving directory '/home/asiia/Documents/work/nodes/mini_v2_node/build/dronecan_sitl/obj'
cursor-bin.AppImage: *** [Makefile:39: sitl_dronecan] Error 2