Merge remote-tracking branch 'remotes/kraxel/tags/pull-serial-20150519-1' into staging

serial: fix multi-pci card error cleanup.

# gpg: Signature made Tue May 19 11:47:29 2015 BST using RSA key ID D3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"

* remotes/kraxel/tags/pull-serial-20150519-1:
  serial: fix multi-pci card error cleanup.

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