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/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index c392c5d..26f335a 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -67,7 +67,7 @@
 
 .globl _TEXT_BASE
 _TEXT_BASE:
-	.word	TEXT_BASE
+	.word	CONFIG_SYS_TEXT_BASE
 
 #if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
 .globl _armboot_start