Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add ARM64TODO comments to ACPI PCI stubs

This will make searching for missing functionalities easier.

Implement stubs for ACPI PCI routines

ACPI driver requires special functions to be provided by machdep code.
Add temporary stubs to satisfy the compiler when both "pci" and "acpi"
are enabled in the kernel configuration file.

Reviewed by: andrew
Obtained from: Semihalf
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3028