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/configs/imxrt1170-evk_defconfig b/configs/imxrt1170-evk_defconfig
index 4edda39..98d6559 100644
--- a/configs/imxrt1170-evk_defconfig
+++ b/configs/imxrt1170-evk_defconfig
@@ -2,7 +2,7 @@
 CONFIG_SYS_DCACHE_OFF=y
 # CONFIG_SPL_SYS_DCACHE_OFF is not set
 CONFIG_ARCH_IMXRT=y
-CONFIG_SYS_TEXT_BASE=0x20240000
+CONFIG_TEXT_BASE=0x20240000
 CONFIG_SYS_MALLOC_LEN=0x8000
 CONFIG_SYS_MALLOC_F_LEN=0x8000
 CONFIG_SPL_GPIO=y