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/psyent/pci5441/config.mk b/board/psyent/pci5441/config.mk
index d72bcee..863a4cb 100644
--- a/board/psyent/pci5441/config.mk
+++ b/board/psyent/pci5441/config.mk
@@ -21,7 +21,7 @@
 # MA 02111-1307 USA
 #
 
-TEXT_BASE = 0x018e0000
+CONFIG_SYS_TEXT_BASE = 0x018e0000
 
 PLATFORM_CPPFLAGS += -mno-hw-div -mno-hw-mul
 PLATFORM_CPPFLAGS += -I$(TOPDIR)/board/$(VENDOR)/include