Merge remote-tracking branch 'remotes/mcayland/tags/qemu-openbios-20180618' into staging

qemu-openbios queue

# gpg: Signature made Mon 18 Jun 2018 19:28:08 BST
# gpg:                using RSA key 5BC2C56FAE0F321F
# gpg: Good signature from "Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>"
# Primary key fingerprint: CC62 1AB9 8E82 200D 915C  C9C4 5BC2 C56F AE0F 321F

* remotes/mcayland/tags/qemu-openbios-20180618:
  Update OpenBIOS images to 8fe6f5f96f built from submodule.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

openbios @ 8fe6f5f9

-Subproject commit 54d959d97fb331708767b2fd4a878efd2bbc41bb
+Subproject commit 8fe6f5f96f6ca39f1f62200be7fa130e929f13f2