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/sniper_defconfig b/configs/sniper_defconfig
index cfa43ad..bae9b0e 100644
--- a/configs/sniper_defconfig
+++ b/configs/sniper_defconfig
@@ -1,7 +1,7 @@
 CONFIG_ARM=y
 # CONFIG_SYS_THUMB_BUILD is not set
 CONFIG_ARCH_OMAP2PLUS=y
-CONFIG_SYS_TEXT_BASE=0x80100000
+CONFIG_TEXT_BASE=0x80100000
 CONFIG_SYS_MALLOC_LEN=0x120000
 CONFIG_SYS_MALLOC_F_LEN=0x400
 CONFIG_NR_DRAM_BANKS=2