cmake simplify uavcan linking

cmake/configs/nuttx_aerocore2_default.cmake

cmake/configs/nuttx_aerofc-v1_default.cmake

cmake/configs/nuttx_auav-x21_default.cmake

cmake/configs/nuttx_crazyflie_default.cmake

cmake/configs/nuttx_esc35-v1_default.cmake

cmake/configs/nuttx_mindpx-v2_default.cmake

cmake/configs/nuttx_px4cannode-v1_default.cmake

cmake/configs/nuttx_px4esc-v1_default.cmake

cmake/configs/nuttx_px4fmu-v1_default.cmake

cmake/configs/nuttx_px4fmu-v2_default.cmake

cmake/configs/nuttx_px4fmu-v2_test.cmake

cmake/configs/nuttx_px4fmu-v3_default.cmake

cmake/configs/nuttx_px4fmu-v4_default.cmake

cmake/configs/nuttx_px4fmu-v4pro_default.cmake

cmake/configs/nuttx_px4fmu-v5_default.cmake

cmake/configs/nuttx_px4nucleoF767ZI-v1_default.cmake

cmake/configs/nuttx_tap-v1_default.cmake

src/firmware/nuttx/CMakeLists.txt

src/modules/uavcan/CMakeLists.txt

src/modules/uavcanesc/CMakeLists.txt