- 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 r257161, r257169, r257178, r257190, r257191

Add pmap_mapdev_attr() and pmap_kenter_attr() interfaces.

Fix concurrency issues with TLB1 updates and make pmap_kextract() search
TLB1 mappings as well

Interrelated improvements to early boot mappings:
- Remove explicit requirement that the SOC registers be found except as an
optimization (although the MPC85XX LAW drivers still require they be found
externally, which should change).
- Remove magic CCSRBAR_VA value.
- Allow bus_machdep.c's early-boot code to handle non 1:1 mappings and
systems not in real-mode or global 1:1 maps in early boot.
- Allow pmap_mapdev() on Book-E to reissue previous addresses if the
area is already mapped. Additionally have it check all mappings, not
just the CCSR area.

Add some extra sanity checking and checks to printf format specifiers.

Bump initial TLB size. The kernel is not necessarily less than 16 MB

Handle (in a slightly ugly way) ePAPR-type loaders that just place a
device tree into r3.

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

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

Extract vendor specific Book-E pieces into separate files and have a common
skeleton (maybe we should kobj-tize this one day).

Note the PPC4xx bit is not connected to the build yet.

Obtained from: AppliedMicro, Semihalf.