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/mvebu_db_armada8k_defconfig b/configs/mvebu_db_armada8k_defconfig
index 2eee745..44aec08 100644
--- a/configs/mvebu_db_armada8k_defconfig
+++ b/configs/mvebu_db_armada8k_defconfig
@@ -1,7 +1,7 @@
 CONFIG_ARM=y
 CONFIG_ARCH_CPU_INIT=y
 CONFIG_ARCH_MVEBU=y
-CONFIG_SYS_TEXT_BASE=0x00000000
+CONFIG_TEXT_BASE=0x00000000
 CONFIG_NR_DRAM_BANKS=2
 CONFIG_TARGET_MVEBU_ARMADA_8K=y
 CONFIG_ENV_SIZE=0x10000