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: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/am335x_gp_evm_defconfig b/configs/am335x_gp_evm_defconfig
index 63b3fce..03c558c 100644
--- a/configs/am335x_gp_evm_defconfig
+++ b/configs/am335x_gp_evm_defconfig
@@ -12,3 +12,4 @@
 CONFIG_SPI_FLASH=y
 CONFIG_RSA=y
 CONFIG_DM_ETH=y
+CONFIG_DM_MMC=y