Merge remote-tracking branch 'remotes/mcayland/tags/qemu-openbios-signed' into staging

Update OpenBIOS images

# gpg: Signature made Wed Jun 17 20:06:06 2015 BST using RSA key ID AE0F321F
# gpg: Good signature from "Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>"

* remotes/mcayland/tags/qemu-openbios-signed:
  Update OpenBIOS images
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

openbios @ 18f02b14

-Subproject commit 5d3db901435ef5a114c9d89461dd0f6d1ef1d44f
+Subproject commit 18f02b14de795c1aab4fe23c1810bfd0944da6aa