am33xx: NAND support

TI AM33XX has the same GPMC controller as OMAP3 so we could just use the
existing omap_gpmc driver. This patch adds adds required
definitions/intialization.

Signed-off-by: Ilya Yanok <ilya.yanok@cogentembedded.com>
diff --git a/arch/arm/include/asm/arch-am33xx/hardware.h b/arch/arm/include/asm/arch-am33xx/hardware.h
index 5bd4bc8..b3922d9 100644
--- a/arch/arm/include/asm/arch-am33xx/hardware.h
+++ b/arch/arm/include/asm/arch-am33xx/hardware.h
@@ -80,6 +80,9 @@
 #define DDRPHY_0_CONFIG_BASE		(CTRL_BASE + 0x1400)
 #define DDRPHY_CONFIG_BASE		DDRPHY_0_CONFIG_BASE
 
+/* GPMC Base address */
+#define GPMC_BASE			0x50000000
+
 /* CPSW Config space */
 #define AM335X_CPSW_BASE		0x4A100000
 #define AM335X_CPSW_MDIO_BASE		0x4A101000