Add UEFI locator for bus_get_device_path, pci acpi

Add a UEFI locator type. It prints the UEFI device names for a FreeBSD
device_t name. It works with PCI and ACPI device nodes. USB forthcoming.

Sponsored by: Netflix
Reviewed by: jhb
Differential Revision: https://reviews.freebsd.org/D32749