drivers: flash: stm32 xspi driver supports the MemoryMapped mode

Adding the support of the memoryMapped mode
to the flash_stm32_xspi driver through the CONFIG_STM32_MEMMAP
That will allow XiP from the external octo_flash
Erase and Write operation must Abort operations.

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