ram: Add driver for MPC83xx

Add a RAM driver for the MPC83xx architecture.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/arch/powerpc/cpu/mpc83xx/spd_sdram.c b/arch/powerpc/cpu/mpc83xx/spd_sdram.c
index bbc8ef0..328a018 100644
--- a/arch/powerpc/cpu/mpc83xx/spd_sdram.c
+++ b/arch/powerpc/cpu/mpc83xx/spd_sdram.c
@@ -10,6 +10,8 @@
  * Xianghua Xiao (X.Xiao@motorola.com)
  */
 
+#ifndef CONFIG_MPC83XX_SDRAM
+
 #include <common.h>
 #include <asm/processor.h>
 #include <asm/io.h>
@@ -924,3 +926,5 @@
 	__asm__ __volatile__ ("isync");
 }
 #endif	/* CONFIG_DDR_ECC */
+
+#endif /* !CONFIG_MPC83XX_SDRAM */