ARM: amlogic: add support for Odroid-HC4 device

The Odroid-HC4 is a variant of the Odroid-C4 board but with a PCIe-SATA bridge
instead of the USB3 ports.

[narmstrong: add missing CONFIG_SYS_LOAD_ADDR from defconfig]
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>