eth: fbnic: Implement Rx queue alloc/start/stop/free

Implement control path parts of Rx queue handling.

The NIC consumes memory in pages. It takes a full page and places
packets into it in a configurable manner (with the ability to define
headroom / tailroom as well as head alignment requirements).
As mentioned in prior patches there are two page submissions queues
one for packet headers and second (optional) for packet payloads.
For now feed both queues from a single page pool.

Use the page pool "fragment" API, as we can't predict upfront
how the page will be sliced.

Signed-off-by: Alexander Duyck <alexanderduyck@fb.com>
Link: https://patch.msgid.link/172079939092.1778861.3780136633831329550.stgit@ahduyck-xeon-server.home.arpa
Signed-off-by: Jakub Kicinski <kuba@kernel.org>