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/topic_miamiplus_defconfig b/configs/topic_miamiplus_defconfig
index add5b62..03d1887 100644
--- a/configs/topic_miamiplus_defconfig
+++ b/configs/topic_miamiplus_defconfig
@@ -4,7 +4,7 @@
 CONFIG_SPL_SYS_DCACHE_OFF=y
 CONFIG_SYS_L2CACHE_OFF=y
 CONFIG_ARCH_ZYNQ=y
-CONFIG_SYS_TEXT_BASE=0x4000000
+CONFIG_TEXT_BASE=0x4000000
 CONFIG_ENV_SIZE=0x8000
 CONFIG_DM_GPIO=y
 CONFIG_DEFAULT_DEVICE_TREE="zynq-topic-miamiplus"