powerpc/mpc85xx:Update MONITOR_LEN for 768KB u-boot size

U-boot binary size has been increased from 512KB to 768KB.

So update CONFIG_SYS_MONITOR_LEN to reflect the same.

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/include/configs/P1023RDS.h b/include/configs/P1023RDS.h
index 0ee75dc..8601eec 100644
--- a/include/configs/P1023RDS.h
+++ b/include/configs/P1023RDS.h
@@ -198,7 +198,7 @@
 	(CONFIG_SYS_INIT_RAM_END - GENERATED_GBL_DATA_SIZE)
 #define CONFIG_SYS_INIT_SP_OFFSET	CONFIG_SYS_GBL_DATA_OFFSET
 
-#define CONFIG_SYS_MONITOR_LEN	(256 * 1024) /* Reserve 256 kB for Mon */
+#define CONFIG_SYS_MONITOR_LEN	(768 * 1024)
 #define CONFIG_SYS_MALLOC_LEN	(6 * 1024 * 1024) /* Reserved for malloc */
 
 #ifndef CONFIG_NAND_SPL