riscv: enable booting HiFive Unmatched from SATA

On the HiFive Unmatched a PCI to SATA adapter may be used to install a SATA
drive. Enable booting from it.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
2 files changed