defconfig: am335x: gp_evm: enable mmc driver model

enable mmc driver model for am335x gp_evm as omap_hsmmc
supports driver model
Signed-off-by: NMugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: NTom Rini <trini@konsulko.com>

configs/am335x_gp_evm_defconfig

@@ -12,3 +12,4 @@ CONFIG_OF_CONTROL=y
 CONFIG_SPI_FLASH=y
 CONFIG_RSA=y
 CONFIG_DM_ETH=y
+CONFIG_DM_MMC=y