Need this for gem5, but was not needed on real hadrware (yet) as it
was always MSI.
Reviewed by: andrew, jhb
Discovered by: andrew
Sponsored by: DARPA/AFRL
Differential Revision: https://reviews.freebsd.org/D5494
Increase MAXCPU number to the maximum known value the existing
hardware can support.
Obtained from: Semihalf
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3405
Add ARM ITS (Interrupt Translation Services) support required
to bring-up message signalled interrupts on some ARM64 platforms.
Obtained from: Semihalf
Sponsored by: The FreeBSD Foundation