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/arm/mach-imx/mx7/Kconfig b/arch/arm/mach-imx/mx7/Kconfig
index 4f9f51c..3c38818 100644
--- a/arch/arm/mach-imx/mx7/Kconfig
+++ b/arch/arm/mach-imx/mx7/Kconfig
@@ -16,7 +16,7 @@
 	select ROM_UNIFIED_SECTIONS
 	imply CMD_FUSE
 
-config SYS_TEXT_BASE
+config TEXT_BASE
 	default 0x87800000
 
 config SPL_TEXT_BASE