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/da850evm_nand_defconfig b/configs/da850evm_nand_defconfig
index f3ae5a7..1586318 100644
--- a/configs/da850evm_nand_defconfig
+++ b/configs/da850evm_nand_defconfig
@@ -3,7 +3,7 @@
 CONFIG_SPL_SKIP_LOWLEVEL_INIT_ONLY=y
 CONFIG_SYS_THUMB_BUILD=y
 CONFIG_ARCH_DAVINCI=y
-CONFIG_SYS_TEXT_BASE=0xc1080000
+CONFIG_TEXT_BASE=0xc1080000
 CONFIG_SYS_MALLOC_LEN=0x110000
 CONFIG_SYS_MALLOC_F_LEN=0x800
 CONFIG_TARGET_DA850EVM=y