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/ls1021atsn_qspi_defconfig b/configs/ls1021atsn_qspi_defconfig
index 61de3e2..bc8e0ed 100644
--- a/configs/ls1021atsn_qspi_defconfig
+++ b/configs/ls1021atsn_qspi_defconfig
@@ -12,6 +12,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="ls1021a-tsn"
 CONFIG_AHCI=y
 CONFIG_DISTRO_DEFAULTS=y
+CONFIG_SYS_LOAD_ADDR=0x82000000
 CONFIG_FIT=y
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_OF_STDOUT_VIA_ALIAS=y