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/p2371-2180_defconfig b/configs/p2371-2180_defconfig
index a4dfed7..c0c36dd 100644
--- a/configs/p2371-2180_defconfig
+++ b/configs/p2371-2180_defconfig
@@ -7,6 +7,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="tegra210-p2371-2180"
 CONFIG_TEGRA210=y
 CONFIG_TARGET_P2371_2180=y
+CONFIG_SYS_LOAD_ADDR=0x80080000
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_OF_SYSTEM_SETUP=y
 CONFIG_CONSOLE_MUX=y