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/doc/board/google/chromebook_samus.rst b/doc/board/google/chromebook_samus.rst
index eab1128..822ba57 100644
--- a/doc/board/google/chromebook_samus.rst
+++ b/doc/board/google/chromebook_samus.rst
@@ -91,7 +91,7 @@
    :fffd8000:	TPL_TEXT_BASE
    :fffa0000:	X86_MRC_ADDR
    :fff90000:	VGA_BIOS_ADDR
-   :ffed0000:	SYS_TEXT_BASE
+   :ffed0000:	TEXT_BASE
    :ffea0000:	X86_REFCODE_ADDR
    :ffe70000:	SPL_TEXT_BASE
    :ffbf8000:	CONFIG_ENV_OFFSET (environemnt offset)