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

drm: Update the device-independent code to match Linux 3.8.13

This update brings few features:
o Support for the setmaster/dropmaster ioctls. For instance, they
are used to run multiple X servers simultaneously.
o Support for minor devices. The only user-visible change is a new
entry in /dev/dri but it is useless at the moment. This is a
first step to support render nodes [1].

The main benefit is to greatly reduce the diff with Linux (at the
expense of an unreadable commit diff). Hopefully, next upgrades will be
easier.

No updates were made to the drivers, beside adapting them to API
changes.

[1] https://en.wikipedia.org/wiki/Direct_Rendering_Manager#Render_nodes

Tested by: Many people
MFC after: 1 month
Relnotes: yes

Merge change from upstream linux kernel submitted by OpenBSD:

drm/radeon: fix-up some float to fixed conversion thinkos

Spotted by Brad Smith when porting to OpenBSD.
Noticed-by: Brad Smith <brad@comstyle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

ref: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1cd73ff7

Remove #ifdef DUMBBELL_WIP in favor of upstream fix.

Phabric: https://phabric.freebsd.org/D423
Reviewed by: dumbbell, jkim
MFC after: 2 weeks

drm/radeon: Import the Radeon KMS driver

This driver is based on Linux 3.8 and a previous effort by kan@.

More informations about this project can be found on the FreeBSD wiki:
https://wiki.freebsd.org/AMD_GPU

The driver is split into:

sys/dev/drm2:
The driver sources.

sys/modules/drm2/radeonkmw:
The driver main kernel module's Makefile.

sys/modules/drm2/radeonkmsfw:
All firmware kernel module Makefiles. There's one directory and one
Makefile for each firmware.

sys/contrib/dev/drm2/radeonkmsfw:
All firmware binary sources.

tools/tools/drm/radeon
Tools to update firmwares or regenerate some headers.

Merging the driver to FreeBSD 9.x may be possible but not a priority for
now.

Help from: kib@, kan@
Tested by: avg@, kwm@, ray@,
Alexander Yerenkow <yerenkow@gmail.com>,
Anders Bolt-Evensen <andersbo87@me.com>,
Denis Djubajlo <stdedjub@googlemail.com>,
J.R. Oldroyd <fbsd@opal.com>,
Mikaël Urankar <mikael.urankar@gmail.com>,
Pierre-Emmanuel Pédron <pepcitron@gmail.com>,
Sam Fourman Jr. <sfourman@gmail.com>,
Wade <wade-is-great@live.com>,
(probably other I forgot...)
HW donations: kyzh, Yakaz