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 18 Jul 2017 17:11:07 BST
# 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:
  tests/ahci-test: Be mean with RAM
  ahci: split public and private interface
  ahci: Isolate public AHCI interface
  ahci: add ahci_get_num_ports

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