ARM: mxs: Let GPMI driver be built by default

Let GPMI driver be built by default.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

arch/arm/configs/mxs_defconfig

@@ -58,6 +58,9 @@ CONFIG_CAN_FLEXCAN=m
 CONFIG_DEVTMPFS=y
 # CONFIG_FIRMWARE_IN_KERNEL is not set
 # CONFIG_BLK_DEV is not set
+CONFIG_MTD=y
+CONFIG_MTD_NAND=y
+CONFIG_MTD_NAND_GPMI_NAND=y
 CONFIG_NETDEVICES=y
 CONFIG_NET_ETHERNET=y
 CONFIG_ENC28J60=y