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/mt8518_ap1_emmc_defconfig b/configs/mt8518_ap1_emmc_defconfig
index e6c2dd0..ac281d3 100644
--- a/configs/mt8518_ap1_emmc_defconfig
+++ b/configs/mt8518_ap1_emmc_defconfig
@@ -7,6 +7,7 @@
 CONFIG_ENV_SIZE=0x1000
 CONFIG_DEFAULT_DEVICE_TREE="mt8518-ap1-emmc"
 CONFIG_TARGET_MT8518=y
+CONFIG_SYS_LOAD_ADDR=0x41000000
 CONFIG_FIT=y
 CONFIG_FIT_SIGNATURE=y
 CONFIG_DEFAULT_FDT_FILE="mt8518-ap1-emmc.dtb"