Driver/DDR: combine ccsr_ddr for 83xx, 85xx and 86xx

Fix ccsr_ddr structure to avoid using typedef. Combine DDR2 and DDR3
structure for 83xx, 85xx and 86xx.

Signed-off-by: York Sun <yorksun@freescale.com>
diff --git a/board/freescale/mpc8540ads/mpc8540ads.c b/board/freescale/mpc8540ads/mpc8540ads.c
index 97a5d19..93288c7 100644
--- a/board/freescale/mpc8540ads/mpc8540ads.c
+++ b/board/freescale/mpc8540ads/mpc8540ads.c
@@ -168,7 +168,8 @@
 phys_size_t fixed_sdram(void)
 {
   #ifndef CONFIG_SYS_RAMBOOT
-	volatile ccsr_ddr_t *ddr = (void *)(CONFIG_SYS_FSL_DDR_ADDR);
+	struct ccsr_ddr __iomem *ddr =
+		(struct ccsr_ddr __iomem *)(CONFIG_SYS_FSL_DDR_ADDR);
 
 	ddr->cs0_bnds = CONFIG_SYS_DDR_CS0_BNDS;
 	ddr->cs0_config = CONFIG_SYS_DDR_CS0_CONFIG;