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/include/configs/smdkc100.h b/include/configs/smdkc100.h
index 595d174..bfd09a0 100644
--- a/include/configs/smdkc100.h
+++ b/include/configs/smdkc100.h
@@ -210,7 +210,7 @@
 #define CONFIG_SYS_MONITOR_LEN		(256 << 10)	/* 256 KiB */
 #define CONFIG_IDENT_STRING		" for SMDKC100"
 
-#if !defined(CONFIG_NAND_SPL) && (TEXT_BASE >= 0xc0000000)
+#if !defined(CONFIG_NAND_SPL) && (CONFIG_SYS_TEXT_BASE >= 0xc0000000)
 #define CONFIG_ENABLE_MMU
 #endif