Platform: stm32l5xx: overload boot_platform_quit

This enables stm32l5xx to use :
- hide protection of mcuboot flash area before
executing the secure application
- MPU protection in mcuboot.

Change-Id: I6de12c2aefadac6552e0b65f3cacacfc73735fd2
Signed-off-by: Michel Jaouen <michel.jaouen@st.com>
3 files changed