powerpc/mpc8xxx: Enable 3-way and 4-way DDR interleaving

Restructure DDR interleaving option to support 3 and 4 DDR controllers
for 2-, 3- and 4-way interleaving.

Signed-off-by: York Sun <yorksun@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
diff --git a/arch/powerpc/cpu/mpc85xx/cpu.c b/arch/powerpc/cpu/mpc85xx/cpu.c
index 8d2ef9f..5ddb294 100644
--- a/arch/powerpc/cpu/mpc85xx/cpu.c
+++ b/arch/powerpc/cpu/mpc85xx/cpu.c
@@ -430,11 +430,21 @@
 		case 0:
 			ddr[i] = (void *)CONFIG_SYS_MPC85xx_DDR_ADDR;
 			break;
-#ifdef CONFIG_SYS_MPC85xx_DDR2_ADDR
+#if defined(CONFIG_SYS_MPC85xx_DDR2_ADDR) && (CONFIG_NUM_DDR_CONTROLLERS > 1)
 		case 1:
 			ddr[i] = (void *)CONFIG_SYS_MPC85xx_DDR2_ADDR;
 			break;
 #endif
+#if defined(CONFIG_SYS_MPC85xx_DDR3_ADDR) && (CONFIG_NUM_DDR_CONTROLLERS > 2)
+		case 2:
+			ddr[i] = (void *)CONFIG_SYS_MPC85xx_DDR3_ADDR;
+			break;
+#endif
+#if defined(CONFIG_SYS_MPC85xx_DDR4_ADDR) && (CONFIG_NUM_DDR_CONTROLLERS > 3)
+		case 3:
+			ddr[i] = (void *)CONFIG_SYS_MPC85xx_DDR4_ADDR;
+			break;
+#endif
 		default:
 			printf("%s unexpected controller number = %u\n",
 				__func__, i);