MFC: 272962

Add a new option, -P, to pkt-gen which reads a single packet from a stored
pcap file and transmits it instead of the default UDP packet.

Reviewed by:	luigi
MFC: 273279

Add new quirks for the latest Samsung SSD, model 850.

Submitted by:	sbruno
MFC r273498: MFV r273494: xz 5.0.7.
MFC r273507: Sync with NetBSD.
MFC r273619: MFV r273617: netcat from OpenBSD 5.6.