Rename CONFIG_SYS_TEXT_BASE to CONFIG_TEXT_BASE

The current name is inconsistent with SPL which uses CONFIG_SPL_TEXT_BASE
and this makes it imposible to use CONFIG_VAL().

Rename it to resolve this problem.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/mips/mach-mscc/lowlevel_init.S b/arch/mips/mach-mscc/lowlevel_init.S
index 91f29ae..0c24cb5 100644
--- a/arch/mips/mach-mscc/lowlevel_init.S
+++ b/arch/mips/mach-mscc/lowlevel_init.S
@@ -21,7 +21,7 @@
 
 	/* Modify ra/s0 such we return to physical NOR location */
 	li	t0, 0x0fffffff
-	li	t1, CONFIG_SYS_TEXT_BASE
+	li	t1, CONFIG_TEXT_BASE
 	and	s0, ra, t0
 	add	s0, s0, t1