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

qemu-sparc update

# gpg: Signature made Thu 08 Mar 2018 07:23:01 GMT
# 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-sparc-signed:
  sparc: fix leon3 casa instruction when MMU is disabled
  hw/sparc/sun4m: Fix implicit creation of "-drive if=scsi" devices

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