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/bcm7260_defconfig b/configs/bcm7260_defconfig
index e8ae5ef..920e882 100644
--- a/configs/bcm7260_defconfig
+++ b/configs/bcm7260_defconfig
@@ -1,7 +1,7 @@
 CONFIG_ARM=y
 CONFIG_SKIP_LOWLEVEL_INIT=y
 CONFIG_ARCH_BCMSTB=y
-CONFIG_SYS_TEXT_BASE=0x10100000
+CONFIG_TEXT_BASE=0x10100000
 CONFIG_SYS_MALLOC_LEN=0x2800000
 CONFIG_SYS_MALLOC_F_LEN=0x400
 CONFIG_TARGET_BCM7260=y