global: Move from bi_memstart/memsize -> gd->ram_base/ram_size

With the planned removal of bi_memstart & bi_memsize, this patch now
moves the references to the better suiting gd->ram_base/ram_size
variables.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/cpu/mpc85xx/traps.c b/arch/powerpc/cpu/mpc85xx/traps.c
index f37a45e..db6ed1f 100644
--- a/arch/powerpc/cpu/mpc85xx/traps.c
+++ b/arch/powerpc/cpu/mpc85xx/traps.c
@@ -37,7 +37,7 @@
  * amount of memory on the system if we're unable to keep all
  * the memory mapped in.
  */
-#define END_OF_MEM (gd->bd->bi_memstart + get_effective_memsize())
+#define END_OF_MEM	(gd->ram_base + get_effective_memsize())
 
 static __inline__ void set_tsr(unsigned long val)
 {