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/board/freescale/imx8qm_mek/uboot-container.cfg b/board/freescale/imx8qm_mek/uboot-container.cfg
index 93c5d39..e25aa76 100644
--- a/board/freescale/imx8qm_mek/uboot-container.cfg
+++ b/board/freescale/imx8qm_mek/uboot-container.cfg
@@ -9,4 +9,4 @@
 SOC_TYPE IMX8QM
 CONTAINER
 IMAGE A35 bl31.bin	0x80000000
-IMAGE A35 u-boot.bin	CONFIG_SYS_TEXT_BASE
+IMAGE A35 u-boot.bin	CONFIG_TEXT_BASE