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/doc/README.COBRA5272 b/doc/README.COBRA5272
index 2d3f706..ae0f148 100644
--- a/doc/README.COBRA5272
+++ b/doc/README.COBRA5272
@@ -89,9 +89,9 @@
 	=> u-boot as single bootloader starting from flash
 
 
-	in board/cobra5272/config.mk TEXT_BASE should be
+	in board/cobra5272/config.mk CONFIG_SYS_TEXT_BASE should be
 
-		TEXT_BASE = 0xffe00000
+		CONFIG_SYS_TEXT_BASE = 0xffe00000
 
 	=> linking address for u-boot as single bootloader stored in flash
 
@@ -128,9 +128,9 @@
 	=> u-boot as RAM version, chainloaded by another bootloader or using bdm cable
 
 
-	in board/cobra5272/config.mk TEXT_BASE should be
+	in board/cobra5272/config.mk CONFIG_SYS_TEXT_BASE should be
 
-		TEXT_BASE = 0x00020000
+		CONFIG_SYS_TEXT_BASE = 0x00020000
 
 	=> target linking address for RAM