Merge remote-tracking branch 'remotes/xtensa/tags/20141110-xtensa' into staging

Xtensa fixes for 2.2:
- fix entry opcode register window checking and add unit test.

# gpg: Signature made Mon 10 Nov 2014 15:01:47 GMT using RSA key ID F83FA044
# gpg: Good signature from "Max Filippov <max.filippov@cogentembedded.com>"
# gpg:                 aka "Max Filippov <jcmvbkbc@gmail.com>"

* remotes/xtensa/tags/20141110-xtensa:
  target-xtensa: add entry overflow test
  target-xtensa: add missing window check for entry

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