Merge remote-tracking branch 'remotes/amit-virtio-rng/tags/rng-for-2.6-1' into staging

rng:
- implement a request queue for rng-random so multiple guest requests
  don't result in vq buffers getting forgotten
- remove unused request cancellation code
- a VM with multiple vq buffers, when migrated, could get in a situation
  where not all buffers are handed back to the guest.  This is now
  fixed.

# gpg: Signature made Thu 03 Mar 2016 12:18:54 GMT using RSA key ID 854083B6
# gpg: Good signature from "Amit Shah <amit@amitshah.net>"
# gpg:                 aka "Amit Shah <amit@kernel.org>"
# gpg:                 aka "Amit Shah <amitshah@gmx.net>"

* remotes/amit-virtio-rng/tags/rng-for-2.6-1:
  virtio-rng: ask for more data if queue is not fully drained
  rng: add request queue support to rng-random
  rng: move request queue cleanup from RngEgd to RngBackend
  rng: move request queue from RngEgd to RngBackend
  rng: remove the unused request cancellation code
  MAINTAINERS: Add an entry for the include/sysemu/rng*.h files

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