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/earthlcd/favr-32-ezkit/config.mk b/board/earthlcd/favr-32-ezkit/config.mk
index 5c919cd..f8bc88d 100644
--- a/board/earthlcd/favr-32-ezkit/config.mk
+++ b/board/earthlcd/favr-32-ezkit/config.mk
@@ -1,4 +1,4 @@
 PLATFORM_RELFLAGS	+= -ffunction-sections -fdata-sections
 PLATFORM_LDFLAGS	+= --gc-sections
-TEXT_BASE		= 0x00000000
+CONFIG_SYS_TEXT_BASE		= 0x00000000
 LDSCRIPT		= $(src)board/earthlcd/favr-32-ezkit/u-boot.lds