configs: dra74_evm: enable mmc driver model

enable mmc driver model for dra74 evm as omap_hsmmc
supports driver model

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

configs/dra74_evm_defconfig

@@ -24,3 +24,4 @@ CONFIG_TIMER=y
 CONFIG_OMAP_TIMER=y
 CONFIG_USB=y
 CONFIG_USB_GADGET=y
+CONFIG_DM_MMC=y