stm32mp2xx_hal_conf.h: remove use_full_assert

Remove the use of full assert in stm32mp2xx_hal_conf.h. As done with
all other STM32 HAL drivers, this prevents build errors when compiling
STM32Cube-based code in Zephyr and allows successful compilation even
if assertion checks are not implemented, as the code still functions
correctly without them.

Signed-off-by: Youssef Zini <youssef.zini@savoirfairelinux.com>