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/MPC8569MDS.h b/include/configs/MPC8569MDS.h
index b815ed0..5f80425 100644
--- a/include/configs/MPC8569MDS.h
+++ b/include/configs/MPC8569MDS.h
@@ -139,8 +139,7 @@
 #define CONFIG_CHIP_SELECTS_PER_CTRL	(2 * CONFIG_DIMM_SLOTS_PER_CTLR)
 
 /* I2C addresses of SPD EEPROMs */
-#define SPD_EEPROM_ADDRESS1    0x51    /* CTLR 0 DIMM 0 */
-#define SPD_EEPROM_ADDRESS2    0x52    /* CTLR 1 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           1024		/* DDR is 1024MB */