Merge remote-tracking branch 'remotes/xtensa/tags/20170124-xtensa' into staging

target/xtensa updates:

- refactor CCOUNT/CCOMPARE (use QEMU timers instead of instruction counting);
- support icount; run target/xtensa TCG tests with icount;
- implement SMP prerequisites: static vector selection, RUNSTALL and RER/WER.

# gpg: Signature made Wed 25 Jan 2017 00:27:51 GMT
# gpg:                using RSA key 0x51F9CC91F83FA044
# gpg: Good signature from "Max Filippov <max.filippov@cogentembedded.com>"
# gpg:                 aka "Max Filippov <jcmvbkbc@gmail.com>"
# Primary key fingerprint: 2B67 854B 98E5 327D CDEB  17D8 51F9 CC91 F83F A044

* remotes/xtensa/tags/20170124-xtensa:
  target-xtensa: implement RER/WER instructions
  target/xtensa: tests: clean up interrupt tests
  target/xtensa: tests: add memctl test
  target/xtensa: implement MEMCTL SR
  target/xtensa: fix ICACHE/DCACHE options detection
  target/xtensa: tests: add ccount write tests
  target/xtensa: tests: replace hardcoded interrupt masks
  target/xtensa: tests: fix timer tests
  target/xtensa: tests: run tests with icount
  target/xtensa: don't continue translation after exception
  target/xtensa: support icount
  target/xtensa: refactor CCOUNT/CCOMPARE
  target/xtensa: implement RUNSTALL
  target/xtensa: add static vectors selection

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>