configs: sama5d27_wlsom1_ek: qspiflash: Enable SPI NOR ethaddr retrieval

CONFIG_SPI_FLASH_SFDP_SUPPORT enables the SFDP Vendor parser,
and for the SST case, the retrieval of the ethaddr from the
SPI NOR flash.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>