- 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

MFC r273856,273863,273963-273965

- Add two new functions to the AGP driver KPI to bind/unbind arbitrary sets
of pages into the GTT.
- Avoid possible overflow in agp_generic_alloc_memory.
- In agp(4) avoid the need to flush all cpu caches with wbinvd between
updating the GTT and flushing the AGP TLB by storing the GTT in
write-combining memory.
- In agp_amd_bind_page don't flush the AGP TLB. It's done by the calling
function.
- agp_generic_unbind_memory: flush AGP TLB before unwiring pages
agp_bind_pages: assert that pages have been wired down

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

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

Remove unneeded header from agp: opt_bus.h

Tested with "make universe"

Approved by: cperciva
MFC after: 1 week

This isn't functionally identical. In some cases a hint to disable
unit 0 would in fact disable all units.

This reverts r241856

Approved by: cperciva (implicit)

Now that device disabling is generic, remove extraneous code from the
device drivers that used to provide this feature.

Reviewed by: des
Approved by: cperciva
MFC after: 1 week

Add a driver for the Apple Uninorth AGP host bridge found in all PowerPC
Macintoshes with an AGP bus.