driver/ddr: Fix DDR4 driver for ARM

Previously the driver was only tested on Power SoCs. Different barrier
instructions are needed for ARM SoCs.

Signed-off-by: York Sun <yorksun@freescale.com>
diff --git a/arch/arm/include/asm/arch-fsl-lsch3/config.h b/arch/arm/include/asm/arch-fsl-lsch3/config.h
index c1c718e..b17410a 100644
--- a/arch/arm/include/asm/arch-fsl-lsch3/config.h
+++ b/arch/arm/include/asm/arch-fsl-lsch3/config.h
@@ -43,7 +43,11 @@
 /* DDR */
 #define CONFIG_SYS_FSL_DDR_LE
 #define CONFIG_VERY_BIG_RAM
+#ifdef CONFIG_SYS_FSL_DDR4
+#define CONFIG_SYS_FSL_DDRC_GEN4
+#else
 #define CONFIG_SYS_FSL_DDRC_ARM_GEN3	/* Enable Freescale ARM DDR3 driver */
+#endif
 #define CONFIG_SYS_FSL_DDR		/* Freescale DDR driver */
 #define CONFIG_SYS_LS2_DDR_BLOCK1_SIZE	((phys_size_t)2 << 30)
 #define CONFIG_MAX_MEM_MAPPED		CONFIG_SYS_LS2_DDR_BLOCK1_SIZE