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/ti/omap2420h4/config.mk b/board/ti/omap2420h4/config.mk
index 3edcde0..ca5ebdf 100644
--- a/board/ti/omap2420h4/config.mk
+++ b/board/ti/omap2420h4/config.mk
@@ -14,15 +14,15 @@
 # (mem base + reserved)
 
 # For use with external or internal boots.
-TEXT_BASE = 0x80e80000
+CONFIG_SYS_TEXT_BASE = 0x80e80000
 
 # Used with full SRAM boot.
 # This is either with a GP system or a signed boot image.
 # easiest, and safest way to go if you can.
-#TEXT_BASE = 0x40270000
+#CONFIG_SYS_TEXT_BASE = 0x40270000
 
 
 # Handy to get symbols to debug ROM version.
-#TEXT_BASE = 0x0
-#TEXT_BASE = 0x08000000
-#TEXT_BASE = 0x04000000
+#CONFIG_SYS_TEXT_BASE = 0x0
+#CONFIG_SYS_TEXT_BASE = 0x08000000
+#CONFIG_SYS_TEXT_BASE = 0x04000000