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/chromebook_samus_tpl_defconfig b/configs/chromebook_samus_tpl_defconfig
index 1e1091f..e922264 100644
--- a/configs/chromebook_samus_tpl_defconfig
+++ b/configs/chromebook_samus_tpl_defconfig
@@ -1,5 +1,5 @@
 CONFIG_X86=y
-CONFIG_SYS_TEXT_BASE=0xffed0000
+CONFIG_TEXT_BASE=0xffed0000
 CONFIG_SYS_MALLOC_F_LEN=0x1a00
 CONFIG_NR_DRAM_BANKS=8
 CONFIG_ENV_SIZE=0x1000