Update OpenBIOS images

# gpg: Signature made Wed 28 Oct 2015 00:02:46 GMT 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: Peter Maydell <peter.maydell@linaro.org>