powerpc: Move CONFIG_SYS_DDR_SIZE to CONFIG_SYS_SDRAM_SIZE

We have a number of CONFIG_SYS_xxx_SIZE options to describe the amount
main memory available.  Rework CONFIG_SYS_DDR_SIZE, which described a
size in number of MiB to use CONFIG_SYS_SDRAM_SIZE which is most often
used as a number of bytes.  Use shifts of this option when required.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/ids8313.h b/include/configs/ids8313.h
index a8bb209..26f0741 100644
--- a/include/configs/ids8313.h
+++ b/include/configs/ids8313.h
@@ -41,7 +41,7 @@
  * Manually set up DDR parameters,
  * as this board has not the SPD connected to I2C.
  */
-#define CONFIG_SYS_DDR_SIZE		256		/* MB */
+#define CONFIG_SYS_SDRAM_SIZE		0x10000000 /* 256 MiB */
 #define CONFIG_SYS_DDR_CONFIG		(CSCONFIG_EN |\
 					 0x00010000 |\
 					 CSCONFIG_ROW_BIT_13 |\