ppc4xx: Fix building PLU405 board

Due to some overlapping sections it's time to update TEXT_BASE
for this board.

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
Signed-off-by: Stefan Roese <sr@denx.de>

board/esd/plu405/config.mk

@@ -25,4 +25,4 @@
 # esd PLU405 boards
 #
 
-TEXT_BASE = 0xFFFA0000
+TEXT_BASE = 0xFFF80000