- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

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

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

- For Cheetah- and Zeus-class CPUs don't flush all unlocked entries from
the TLBs in order to get rid of the user mappings but instead traverse
them an flush only the latter like we also do for the Spitfire-class.
Also flushing the unlocked kernel entries can cause instant faults which
when called from within cpu_switch() are handled with the scheduler lock
held which in turn can cause timeouts on the acquisition of the lock by
other CPUs. This was easily seen with a 16-core V890 but occasionally
also happened with 2-way machines.
While at it, move the SPARC64-V support code entirely to zeus.c. This
causes a little bit of duplication but is less confusing than partially
using Cheetah-class bits for these.
- For SPARC64-V ensure that 4-Mbyte page entries are stored in the 1024-
entry, 2-way set associative TLB.
- In {d,i}tlb_get_data_sun4u() turn off the interrupts in order to ensure
that ASI_{D,I}TLB_DATA_ACCESS_REG actually are read twice back-to-back.

Tested by: Peter Jeremy (16-core US-IV), Michael Moll (2-way SPARC64-V)

Add support for SPARC64 V (and where it already makes sense for other
HAL/Fujitsu) CPUs. For the most part this consists of fleshing out the
MMU and cache handling, it doesn't add pmap optimizations possible with
these CPU, yet, though.
With these changes FreeBSD runs stable on Fujitsu Siemens PRIMEPOWER 250
and likely also other models based on SPARC64 V like 450, 650 and 850.
Thanks go to Michael Moll for providing access to a PRIMEPOWER 250.