- 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 r279385, r279902, r281412:

Merge latest dts files (commit c8c1b3a77934768c7f7a4a9c10140c8bec529059)
from the git tree.

File names with commas in them cause issues for freebsd-update. We
don't actually use these files at the moment, so eliminate them until
we actually do. In the mean time, freebsd-update will be updated
to eliminate the issues.

The GNU Amlogic DTS files have some errors (e.g. bad register
address, bad IRQ, etc) which are fixed by this patch.

MFC r262606, r262607, r262608, r262609, r262610, r269528, r269609, r271133:

- Move imported dts source from sys/contrib/dts/ to sys/gnu/dts.
- Fix some missing properties.
- Import dts-related header files.
- Update everything to latest vendor branch representing 3.17-rc2
level of Linux DTS API.

These file have a, possibly dubious, GPL claim. Until that's sorted, move to gnu.

Correct initial import script

Initial import of Linux/Vendor DTS files for various embedded boards.