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

qemu-sparc queue

# gpg: Signature made Mon 18 Jun 2018 18:43:24 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-sparc-20180618:
  SPARC64: add icount support
  hw/sparc/sun4m: Fix problems with device introspection
  hw/sparc64/sun4u: Fix introspection by converting prom instance_init to realize

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