Rename TEXT_BASE into CONFIG_SYS_TEXT_BASE

The change is currently needed to be able to remove the board
configuration scripting from the top level Makefile and replace it by
a simple, table driven script.

Moving this configuration setting into the "CONFIG_*" name space is
also desirable because it is needed if we ever should move forward to
a Kconfig driven configuration system.

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/arch/powerpc/cpu/mpc86xx/start.S b/arch/powerpc/cpu/mpc86xx/start.S
index 596053f..0d02279 100644
--- a/arch/powerpc/cpu/mpc86xx/start.S
+++ b/arch/powerpc/cpu/mpc86xx/start.S
@@ -848,8 +848,8 @@
 	stw	r5, 0(r4) /* Store physical value of CCSR */
 	isync
 
-	lis	r5, TEXT_BASE@h
-	ori	r5,r5,TEXT_BASE@l
+	lis	r5, CONFIG_SYS_TEXT_BASE@h
+	ori	r5,r5,CONFIG_SYS_TEXT_BASE@l
 	lwz	r5, 0(r5)
 	isync