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/sei510_defconfig b/configs/sei510_defconfig
index 59036cc..30b49cc 100644
--- a/configs/sei510_defconfig
+++ b/configs/sei510_defconfig
@@ -2,7 +2,7 @@
 CONFIG_SYS_BOARD="sei510"
 CONFIG_SYS_CONFIG_NAME="sei510"
 CONFIG_ARCH_MESON=y
-CONFIG_SYS_TEXT_BASE=0x01000000
+CONFIG_TEXT_BASE=0x01000000
 CONFIG_SYS_MALLOC_LEN=0x8000000
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_ENV_SIZE=0x10000