mpc83xx: Get rid of CONFIG_SYS_DDR_BASE

CONFIG_SYS_DDR_BASE is specific to mpc83xx an is always set to the same
value as CONFIG_SYS_SDRAM_BASE. Just use CONFIG_SYS_SDRAM_BASE instead.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/include/configs/MPC8313ERDB_NOR.h b/include/configs/MPC8313ERDB_NOR.h
index 2a39ffa..169cc09 100644
--- a/include/configs/MPC8313ERDB_NOR.h
+++ b/include/configs/MPC8313ERDB_NOR.h
@@ -58,9 +58,8 @@
 /*
  * DDR Setup
  */
-#define CONFIG_SYS_DDR_BASE		0x00000000 /* DDR is system memory*/
-#define CONFIG_SYS_SDRAM_BASE		CONFIG_SYS_DDR_BASE
-#define CONFIG_SYS_DDR_SDRAM_BASE	CONFIG_SYS_DDR_BASE
+#define CONFIG_SYS_SDRAM_BASE		0x00000000 /* DDR is system memory*/
+#define CONFIG_SYS_DDR_SDRAM_BASE	CONFIG_SYS_SDRAM_BASE
 
 /*
  * Manually set up DDR parameters, as this board does not