board: ge: ppd: Enable CONFIG_DM_MMC

Use MMC device model, and remove USDHC pin configuration code since the
pinctrl driver is used.

Signed-off-by: Ian Ray <ian.ray@ge.com>
diff --git a/configs/mx53ppd_defconfig b/configs/mx53ppd_defconfig
index 04537c5..ec3bc10 100644
--- a/configs/mx53ppd_defconfig
+++ b/configs/mx53ppd_defconfig
@@ -46,3 +46,7 @@
 CONFIG_CMD_DM=y
 CONFIG_OF_CONTROL=y
 CONFIG_DEFAULT_DEVICE_TREE="imx53-ppd"
+CONFIG_DM_MMC=y
+CONFIG_BLK=y
+CONFIG_PINCTRL=y
+CONFIG_PINCTRL_IMX5=y