Attempt to map msk(4) interrupt via MSI.

Attempt to map msk(4) interrupt via MSI.

The device tree that ships with the overdrive 1000 has an interrupt-map
property that is known to be wrong.  Using MSI on msk makes the builtin
Ethernet on the overdrive 1000 work.

Tested on arm64 with
"Marvell Yukon 88E8059" rev 0x00, Yukon-2 Optima (0x1)

and i386 with
"Marvell Yukon 88E8072" rev 0x10, Yukon-2 Extreme rev. B0 (0x2)

Committing this early in the release cycle to try find cases where using
MSI doesn't work.

Based on part of an earlier patch from jmatthew@
ok jmatthew@ kettenis@