drivers: flash: stm32wb: Flush caches after erase
drivers: flash: stm32wb: Flush caches after erase

This commit fixes sporadic kernel panics when writing big data chunks
to the flash. (data bus errors). Just like the stm32g4 does.

Signed-off-by: Francois Ramu <b83adc7f8a23ee911a37fcb61c4033581aae0b7a@st.com>

nashif/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr,nashif/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr