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/tb100_defconfig b/configs/tb100_defconfig
index 42f7b3c..361853a 100644
--- a/configs/tb100_defconfig
+++ b/configs/tb100_defconfig
@@ -1,6 +1,6 @@
 CONFIG_ARC=y
 CONFIG_TARGET_TB100=y
-CONFIG_SYS_TEXT_BASE=0x84000000
+CONFIG_TEXT_BASE=0x84000000
 CONFIG_SYS_MALLOC_LEN=0x20000
 CONFIG_SYS_MALLOC_F_LEN=0x400
 CONFIG_ENV_SIZE=0x800