Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix svn properties and remove a P4 keyword.

Using svn cp rather than cp to copy these files over had the benefit
of preserving their history. It had the problem that it also copied
over mergeinfo data. Since we're retiring the projects/mips branch,
I'm removing the svn:mergeinfo property from them all.

Submitted by: jhb

Merge from projects/mips to head by hand.

Copy over the SWARM.hints file.

Add config file for SWARM board, a sybyte SB-1-based board by
Broadcom. BCM-91250.

Submitted by: Neelkanth Natu