mx7dsabre: Remove warning about DM_SPI_FLASH

This defconfig doesn't need it.
Signed-off-by: NJoris Offouga <offougajoris@gmail.com>

configs/mx7dsabresd_defconfig

@@ -51,9 +51,6 @@ CONFIG_MMC_IO_VOLTAGE=y
 CONFIG_MMC_UHS_SUPPORT=y
 CONFIG_MMC_HS200_SUPPORT=y
 CONFIG_FSL_USDHC=y
-CONFIG_MTD=y
-CONFIG_SPI_FLASH=y
-CONFIG_SPI_FLASH_EON=y
 CONFIG_PHYLIB=y
 CONFIG_PHY_BROADCOM=y
 CONFIG_DM_ETH=y