Merge remote-tracking branch 'remotes/philmd-gitlab/tags/fw_cfg-next-pull-request...

Merge remote-tracking branch 'remotes/philmd-gitlab/tags/fw_cfg-next-pull-request' into staging

Fix the fw_cfg reboot-timeout=-1 special value, add a test for it.

# gpg: Signature made Sun 03 Nov 2019 22:21:02 GMT
# gpg:                using RSA key 89C1E78F601EE86C867495CBA2A3FD6EDEADC0DE
# gpg: Good signature from "Philippe Mathieu-Daudé (Phil) <[email protected]>" [marginal]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 89C1 E78F 601E E86C 8674  95CB A2A3 FD6E DEAD C0DE

* remotes/philmd-gitlab/tags/fw_cfg-next-pull-request:
  tests/fw_cfg: Test 'reboot-timeout=-1' special value
  fw_cfg: Allow reboot-timeout=-1 again

Signed-off-by: Peter Maydell <[email protected]>