ti816x_evm: Enable DM_MMC

This platform is already using DM in general and the MMC controller is
the early generation of what is compatible with "ti,omap4-hsmmc" so
enable DM_MMC (which in turn gets BLK enabled).

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/ti816x_evm_defconfig b/configs/ti816x_evm_defconfig
index 98322b8..453b88f 100644
--- a/configs/ti816x_evm_defconfig
+++ b/configs/ti816x_evm_defconfig
@@ -49,6 +49,7 @@
 CONFIG_DM=y
 CONFIG_DM_I2C=y
 CONFIG_SYS_I2C_OMAP24XX=y
+CONFIG_DM_MMC=y
 CONFIG_MMC_OMAP_HS=y
 CONFIG_MTD=y
 CONFIG_MTD_RAW_NAND=y