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/hikey960_defconfig b/configs/hikey960_defconfig
index 316a042..b11ec30 100644
--- a/configs/hikey960_defconfig
+++ b/configs/hikey960_defconfig
@@ -7,6 +7,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="hi3660-hikey960"
 CONFIG_IDENT_STRING="\nHikey960"
 CONFIG_DISTRO_DEFAULTS=y
+CONFIG_SYS_LOAD_ADDR=0x80000
 CONFIG_BOOTDELAY=3
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttyAMA6,115200n8 root=/dev/mmcblk0p2 rw"