update feather can board property

Author: jepler

boards.txt

@@ -729,7 +729,7 @@ adafruit_feather_m4_can.build.mcu=cortex-m4
 #adafruit_feather_m4_can.build.f_cpu=120000000L
 adafruit_feather_m4_can.build.usb_product="Adafruit Feather M4 CAN"
 adafruit_feather_m4_can.build.usb_manufacturer="Adafruit LLC"
-adafruit_feather_m4_can.build.board=FEATHER_M4
+adafruit_feather_m4_can.build.board=FEATHER_M4_CAN
 adafruit_feather_m4_can.build.core=arduino
 adafruit_feather_m4_can.build.extra_flags=-D__SAME51J19A__ -DADAFRUIT_FEATHER_M4_EXPRESS -DADAFRUIT_FEATHER_M4_CAN -D__SAMD51__ {build.usb_flags} -D__FPU_PRESENT -DARM_MATH_CM4 -mfloat-abi=hard -mfpu=fpv4-sp-d16
 adafruit_feather_m4_can.build.ldscript=linker_scripts/gcc/flash_with_bootloader.ld