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/pm9261_defconfig b/configs/pm9261_defconfig
index d82d92a..0245cc5 100644
--- a/configs/pm9261_defconfig
+++ b/configs/pm9261_defconfig
@@ -1,7 +1,7 @@
 CONFIG_ARM=y
 CONFIG_ARCH_CPU_INIT=y
 CONFIG_ARCH_AT91=y
-CONFIG_SYS_TEXT_BASE=0
+CONFIG_TEXT_BASE=0
 CONFIG_SYS_MALLOC_LEN=0x50000
 CONFIG_TARGET_PM9261=y
 CONFIG_NR_DRAM_BANKS=1