Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

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

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Buffers which can be memory mapped into userspace should never be
freed. Recycle the buffers instead. This patch also fixes a panic at
reboot issue when an UDL adapter is attached to the system.

Reduce number of memory buffers a bit.

Import USB display link driver from OpenBSD. Support for compression
has been removed and the driver has been greatly simplified and
optimised for FreeBSD. The driver is currently not built by default.

Requested by: Bruce Simpson <bms@fastmail.net>