- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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.

Cleanup in r600_blit

- Don't bother to assign vb until we know we have enough space
- Add variables for sx2, sy2, dx2, dy2 so that these aren't
calculated over and over, also reduce chance of errors.
- Use switch to assign color/format

MFC after: 3 days

Fix blitter support for RS880 chips

MFC after: 3 days

Fix blit pitch for 4 byte transfers on r600.

MFC after: 1 week

Add a couple of small fixes from the AMD folks.

- max tex height is 8192
- increment src/dst by the full transfer amount

MFC after: 3 days

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