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

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

# gpg: Signature made Tue 31 Oct 2017 23:01:18 GMT
# gpg:                using RSA key 0x7DEF8106AAFC390E
# gpg: Good signature from "John Snow (John Huston) <jsnow@redhat.com>"
# Primary key fingerprint: FAEB 9711 A12C F475 812F  18F2 88A9 064D 1835 61EB
#      Subkey fingerprint: F9B7 ABDB BCAC DF95 BE76  CBD0 7DEF 8106 AAFC 390E

* remotes/jnsnow/tags/ide-pull-request:
  ide: avoid referencing NULL dev in rotational rate setting
  hw/ide/ahci: Move allwinner code into a separate file

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