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/board/ns9750dev/lowlevel_init.S b/board/ns9750dev/lowlevel_init.S
index 3a09786..ba5ff81 100644
--- a/board/ns9750dev/lowlevel_init.S
+++ b/board/ns9750dev/lowlevel_init.S
@@ -68,7 +68,7 @@
 .endm
 
 _TEXT_BASE:
-	.word	TEXT_BASE	@ sdram load addr from config.mk
+	.word	CONFIG_SYS_TEXT_BASE	@ sdram load addr from config.mk
 _PHYS_FLASH:
 	.word	PHYS_FLASH_1    @ real flash address (without mirroring)
 _CAS_LATENCY: