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/ls1021atwr_nor_defconfig b/configs/ls1021atwr_nor_defconfig
index b8044cf..d7d28a6 100644
--- a/configs/ls1021atwr_nor_defconfig
+++ b/configs/ls1021atwr_nor_defconfig
@@ -13,6 +13,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="ls1021a-twr-duart"
 CONFIG_AHCI=y
 CONFIG_DISTRO_DEFAULTS=y
+CONFIG_SYS_LOAD_ADDR=0x82000000
 CONFIG_FIT=y
 CONFIG_FIT_VERBOSE=y
 CONFIG_OF_BOARD_SETUP=y