powerpc/8xxx: Refactor fsl_ddr_get_spd into common code from board

Move fsl_ddr_get_spd into common mpc8xxx/ddr/main.c as most boards
pretty much do the same thing.  The only variations are in how many
controllers or DIMMs per controller exist.  To make this work we
standardize on the names of the SPD_EEPROM_ADDRESS defines based on the
use case of the board.

We allow boards to override get_spd to either do board specific fixups
to the SPD data or deal with any unique behavior of how the SPD eeproms
are wired up.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/include/configs/MPC8610HPCD.h b/include/configs/MPC8610HPCD.h
index 03ee394..7b25e07 100644
--- a/include/configs/MPC8610HPCD.h
+++ b/include/configs/MPC8610HPCD.h
@@ -108,7 +108,7 @@
 #define CONFIG_DIMM_SLOTS_PER_CTLR	1
 #define CONFIG_CHIP_SELECTS_PER_CTRL	(2 * CONFIG_DIMM_SLOTS_PER_CTLR)
 
-#define SPD_EEPROM_ADDRESS1	0x51	/* CTLR 0 DIMM 0 */
+#define SPD_EEPROM_ADDRESS	0x51	/* CTLR 0 DIMM 0 */
 
 /* These are used when DDR doesn't use SPD.  */
 #define CONFIG_SYS_SDRAM_SIZE	256		/* DDR is 256MB */