Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2019-02-18' into staging

QAPI patches for 2019-02-18

# gpg: Signature made Mon 18 Feb 2019 13:44:30 GMT
# gpg:                using RSA key 3870B400EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2019-02-18:
  qapi: move RTC_CHANGE to the target schema
  qmp: Deprecate query-events in favor of query-qmp-schema
  Revert "qapi-events: add 'if' condition to implicit event enum"
  qapi: remove qmp_unregister_command()
  qapi: make query-cpu-definitions depend on specific targets
  qapi: make query-cpu-model-expansion depend on s390 or x86
  qapi: make query-gic-capabilities depend on TARGET_ARM
  target.json: add a note about query-cpu* not being s390x-specific
  qapi: make s390 commands depend on TARGET_S390X
  qapi: make rtc-reset-reinjection and SEV depend on TARGET_I386
  qapi: New module target.json
  build: Deal with all of QAPI's .o in qapi/Makefile.objs
  build-sys: move qmp-introspect per target
  qapi: Generate QAPIEvent stuff into separate files
  qapi: Prepare for system modules other than 'builtin'
  qapi: Clean up modular built-in code generation a bit
  qapi: Fix up documentation for recent commit a9529100
  qapi: Belatedly document modular code generation

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