Convert CONFIG_SYS_LOAD_ADDR to Kconfig

Now that we have consistent usage, migrate this symbol to Kconfig.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Rick Chen <rick@andestech.com>
diff --git a/configs/vocore2_defconfig b/configs/vocore2_defconfig
index 9ca2852..3cf6130 100644
--- a/configs/vocore2_defconfig
+++ b/configs/vocore2_defconfig
@@ -18,6 +18,7 @@
 CONFIG_ENV_VARS_UBOOT_CONFIG=y
 CONFIG_SYS_BOOT_GET_CMDLINE=y
 CONFIG_SYS_BOOT_GET_KBD=y
+CONFIG_SYS_LOAD_ADDR=0x80100000
 CONFIG_FIT=y
 CONFIG_FIT_SIGNATURE=y
 CONFIG_LEGACY_IMAGE_FORMAT=y