parser.
This allows us to use the EROM parser API in cases where the standard bus
space I/O APIs are unsuitable. In particular, this will allow us to parse
the device enumeration table directly from bhndb(4) drivers, prior to
full attach and configuration of the bridge.
Approved by: adrian (mentor)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D12510