MFC 267284

MFC  267284
Fixes from Fanco Ficthner on transparent mode

* The way rings are updated changed with the last API bump.
  Also sync ->head when moving slots in netmap_sw_to_nic().

* Remove a crashing selrecord() call.

* Unclog the logic surrounding netmap_rxsync_from_host().

* Add timestamping to RX host ring.

* Remove a couple of obsolete comments.

Submitted by:	Franco Fichtner
MFC after:	3 days
Sponsored by:	Packetwerk

git-svn-id: svn://svn.freebsd.org/base/stable/10@267334 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f