mpc512x: Streamlined fixed_sdram() init sequence.

Signed-off-by: Martha M Stan <mmarx@silicontkx.com>

Minor cleanup:

Re-ordered default_mddrc_config[] to have matching indices.

This allows to use the same index "N" for source and target fields;
before, we had code like this

	out_be32(&im->mddrc.ddr_time_config2, mddrc_config[3]);

which always looked like a copy & paste error because 2 != 3.

Also, use NULL when meaning a null pointer.

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/include/asm-ppc/immap_512x.h b/include/asm-ppc/immap_512x.h
index 24e6c69..79cdd80 100644
--- a/include/asm-ppc/immap_512x.h
+++ b/include/asm-ppc/immap_512x.h
@@ -341,6 +341,10 @@
 	u32 res2[0x3AD];
 } ddr512x_t;
 
+/* MDDRC SYS CFG and Timing CFG0 Registers */
+#define MDDRC_SYS_CFG_EN	0xF0000000
+#define MDDRC_SYS_CFG_CMD_MASK	0x10000000
+#define MDDRC_REFRESH_ZERO_MASK	0x0000FFFF
 
 /*
  * DMA/Messaging Unit
diff --git a/include/asm-ppc/mpc512x.h b/include/asm-ppc/mpc512x.h
index 20456f5..8ef0d9c 100644
--- a/include/asm-ppc/mpc512x.h
+++ b/include/asm-ppc/mpc512x.h
@@ -50,7 +50,7 @@
 /*
  * Prototypes
  */
-extern long int fixed_sdram(void);
+extern long int fixed_sdram(u32 *mddrc_config, u32 *dram_init_seq, int seq_sz);
 extern int mpc5121_diu_init(void);
 extern void ide_set_reset(int idereset);