mtd: spi: Add a new option SPL_SPI_FLASH_MTD to Kconfig

To allow SPI_FLASH_MTD being enabled separately in SPL we add a new
option. The only user currently is the stm32mp15_basic board.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Acked-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
1 file changed