setting HAL_USE_CAN uses the ChibiOS CAN driver instead of the AP_HAL
CAN driver. This is only used on the f103-periph as it significantly
reduces the size of the bootloader, which allows for f103 builds to
fit in the limited flash
on all other builds we are much better off using the HAL CAN driver as
it is much faster
this allows for CAN firmware update using f405-MatekGPS bootloader by
fixing a typo, then moves storage to allow the bootloader with can to
fit on the board
this will allow CAN update of peripheral firmware for Matek GPS and
airspeed sensors
Andrew Tridgell
mateksys