samples: drivers: spi flash in mem mapped on stm32h7rs board

Define the Memory mapped mode on the nucleo_hs7s3l8 board
to read and write the external NOR octo-flash

Signed-off-by: Francois Ramu <[email protected]>

Author: FRASTM

samples/drivers/spi_flash/boards/nucleo_h7s3l8.conf

@@ -0,0 +1,5 @@
+CONFIG_STM32_MEMMAP=y
+
+CONFIG_LOG=y
+CONFIG_FLASH_LOG_LEVEL_INF=y
+