Merge remote-tracking branch 'remotes/jasowang/tags/net-pull-request' into staging

# gpg: Signature made Fri 20 Jan 2017 02:58:57 GMT
# gpg:                using RSA key 0xEF04965B398D6211
# gpg: Good signature from "Jason Wang (Jason Wang on RedHat) <jasowang@redhat.com>"
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 215D 46F4 8246 689E C77F  3562 EF04 965B 398D 6211

* remotes/jasowang/tags/net-pull-request:
  tap: fix memory leak on failure in net_init_tap()
  hw/pci: use-after-free in pci_nic_init_nofail when nic device fails to initialize
  hw/net/dp8393x: Avoid unintentional sign extensions on addresses
  m68k: QOMify the MCF Fast Ethernet Controller device
  net: optimize checksum computation
  docs: Fix description of the sentence

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