- Copy stable/10@285827 to releng/10.2 in preparation for 10.2-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.2.
- Update default pkg(8) configuration to use the quarterly branch.[1]

Discussed with: re, portmgr [1]
Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

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

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

Make drm(4) build, if not work reliably, on PowerPC.

Rework how drm maps are handled.

* On 32 bit platforms we steal the upper 4 bits of the map handle
to store a unique map id.
* On 64 bit platforms we steal the upper 24 bits.

Resolves issues where the offsets that are handed to mmap may overlap the VRAM on some cards.

Tested on: radeon, intel, mga, and via.

This will break nouveau. I will spin new patches shortly.

Fix offset handling

MFC after: 1 week

Add kernel support for Radeon R6/7xx 3D.

You will still need Mesa from git and possibly an updated DDX driver,
but this is working fairly well now.

MFC after: 2 weeks