powerpc/mpc85xx:Avoid fix address of bootpg section

It is not necessary for bootpg to be present at text + 512KB.
With increase of u-boot size (768KB), bootpg section's address
cannot be fixed.

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/arch/powerpc/cpu/mpc85xx/u-boot.lds b/arch/powerpc/cpu/mpc85xx/u-boot.lds
index b34d212..0b9086d 100644
--- a/arch/powerpc/cpu/mpc85xx/u-boot.lds
+++ b/arch/powerpc/cpu/mpc85xx/u-boot.lds
@@ -12,6 +12,10 @@
 #define RESET_VECTOR_ADDRESS	0xfffffffc
 #endif
 
+#ifndef CONFIG_SYS_MONITOR_LEN
+#define CONFIG_SYS_MONITOR_LEN	0x80000
+#endif
+
 OUTPUT_ARCH(powerpc)
 ENTRY(_start_e500)
 
@@ -85,7 +89,7 @@
   {
     KEEP(arch/powerpc/cpu/mpc85xx/start.o (.bootpg))
   } :text = 0xffff
-  . = ADDR(.text) + 0x80000;
+  . = ADDR(.text) + CONFIG_SYS_MONITOR_LEN;
 #else
   .bootpg RESET_VECTOR_ADDRESS - 0xffc :
   {