mpc83xx: implement board_add_ram_info

add board_add_ram_info, to make memory diagnostic output more
consistent. u-boot banner output now looks like:

DRAM:  256 MB (DDR1, 64-bit, ECC on)

and for boards with SDRAM on the local bus, a line such as this is
added:

SDRAM: 64 MB (local bus)

also replaced some magic numbers with their equivalent define names.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
diff --git a/include/mpc83xx.h b/include/mpc83xx.h
index 829dbf9..4d32c6a 100644
--- a/include/mpc83xx.h
+++ b/include/mpc83xx.h
@@ -705,8 +705,9 @@
 #define SDRAM_CFG_SREN			0x40000000
 #define SDRAM_CFG_ECC_EN		0x20000000
 #define SDRAM_CFG_RD_EN			0x10000000
-#define SDRAM_CFG_SDRAM_TYPE		0x03000000
-#define SDRAM_CFG_SDRAM_TYPE_DDR	0x02000000
+#define SDRAM_CFG_SDRAM_TYPE_DDR1	0x02000000
+#define SDRAM_CFG_SDRAM_TYPE_DDR2	0x03000000
+#define SDRAM_CFG_SDRAM_TYPE_MASK	0x07000000
 #define SDRAM_CFG_SDRAM_TYPE_SHIFT	24
 #define SDRAM_CFG_DYN_PWR		0x00200000
 #define SDRAM_CFG_32_BE			0x00080000