Merge remote-tracking branch 'remotes/jnsnow/tags/ide-pull-request' into staging

# gpg: Signature made Fri 18 Sep 2015 15:59:02 BST using RSA key ID AAFC390E
# gpg: Good signature from "John Snow (John Huston) <jsnow@redhat.com>"

* remotes/jnsnow/tags/ide-pull-request:
  ahci: clean up initial d2h semantics
  ahci: remove cmd_fis argument from write_fis_d2h
  ahci: fix signature generation
  ahci: remove dead reset code
  atapi: abort transfers with 0 byte limits
  ide: fix ATAPI command permissions
  ide-test: add cdrom dma test
  ide-test: add cdrom pio test
  qtest/ahci: export generate_pattern
  qtest/ahci: use generate_pattern everywhere
  ide: unify io_buffer_offset increments

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