imx6: aristainetos: convert to DM_MMC

Enable DM_MMC support.

Signed-off-by: Heiko Schocher <hs@denx.de>
diff --git a/configs/aristainetos2_defconfig b/configs/aristainetos2_defconfig
index 65702c0..52c28d9 100644
--- a/configs/aristainetos2_defconfig
+++ b/configs/aristainetos2_defconfig
@@ -53,6 +53,7 @@
 CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_ENV_OFFSET_REDUND=0xE0000
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_DM_MMC=y
 CONFIG_FSL_USDHC=y
 CONFIG_MTD=y
 CONFIG_MTD_RAW_NAND=y