powerpc/mpc85xx:Increase binary size for P, B & T series boards.

u-boot binary size for Freescale mpc85xx platforms is 512KB.
This has been reached to upper limit for some of the platforms causig
linker error.

So, Increase the u-boot binary size to 768KB.

Signed-off-by: York Sun <yorksun@freescale.com>
Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
diff --git a/board/freescale/p1023rds/README b/board/freescale/p1023rds/README
index 685f5da..d382551 100644
--- a/board/freescale/p1023rds/README
+++ b/board/freescale/p1023rds/README
@@ -62,8 +62,8 @@
 NOR flash boot:
 	=> tftp 1000000 u-boot.bin
 	=> protect off all
-	=> erase eff80000 efffffff
-	=> cp.b 1000000 eff80000 80000
+	=> erase eff40000 efffffff
+	=> cp.b 1000000 eff40000 c0000
 
 NAND flash boot:
 	=> tftp 1000000 u-boot-nand.bin