target-arm: A64: Add SIMD two reg misc

This is a sub-set of the whole opcode field including SIMD vector
versions of:

* XTN, XTN2
* FABS, FNEG
* NOT, RBIT
* NEG

The following are additions to the original SUSE tree.

* REV, REV32, REV64
* CNT

---

v2 (ajb):
  - convert to new APIs

v3 (ajb):
  - some fixups for XTN and XTN2
  - fix tcg temp leaks (use auto-free due to exit paths)
  - use neon_cnt helper for CNT
  - add REV16..64 vector versions
  - rm scalar code (not in this leg of decoder)
target-arm: A64: add wrapper for ARM NEON functions

Given the similarity between a lot of the 64bit AdvSIMD functions and
the existing 32 bit ARM NEON functions we can get a lot of re-use by
using them. The wrapper takes care of shifting the values between 64 bit
and 32 bit worlds.
translate-a64.c: add a debug helper trace macro

This just makes it easier to drop TRACE_DECODE statements all over the
place instead of fprintfs.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---

v2 (ajb)
   - checkpatch.pl fixes
rm unused field
scripts/qemu-binfmt-conf.sh: re-factor and clean-up

I was looking to set-up for development but found the script made some
hard-coded assumptions. It doesn't seem the script is used by the
distros but if it had a little more love maybe it would be ;-)

* Add usage() instructions
* Move all registering to a single function
* Check for existence of executable qemu before registering
* Add -d (devel) mode for subscribing in-src tree binaries
* error handling when setting binfmt fails
* add support for aarch64
scripts/qemu-binfmt-check.py: a binfmt checker

This script allows you to check if a given binary will match against any
of the currently registered binfmts on the system.

---

v2 (ajb):
   - cleaned up whitespace and checkpatch fixes
linux-user: Implement sendmmsg syscall

Glibc when built for newer kernels assumes that the sendmmsg syscall is available.
Without it, dns resolution simply fails to work.

Wrap the syscall with existing infrastructure so that we don't have a host dependency
on sendmmsg.

Signed-off-by: Alexander Graf <agraf@suse.de>