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/sama7g5ek_mmc_defconfig b/configs/sama7g5ek_mmc_defconfig
index 9aad9ce..5b42fc6 100644
--- a/configs/sama7g5ek_mmc_defconfig
+++ b/configs/sama7g5ek_mmc_defconfig
@@ -1,6 +1,6 @@
 CONFIG_ARM=y
 CONFIG_ARCH_AT91=y
-CONFIG_SYS_TEXT_BASE=0x66f00000
+CONFIG_TEXT_BASE=0x66f00000
 CONFIG_SYS_MALLOC_F_LEN=0x11000
 CONFIG_TARGET_SAMA7G5EK=y
 CONFIG_NR_DRAM_BANKS=1