Merge remote-tracking branch 'remotes/vivier/tags/q800-for-6.2-pull-request' into staging

Q800 Pull request 20210929

NuBus cleanup and improvement

# gpg: Signature made Wed 29 Sep 2021 10:27:51 BST
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier/tags/q800-for-6.2-pull-request:
  q800: configure nubus available slots for Quadra 800
  q800: wire up nubus IRQs
  nubus: add support for slot IRQs
  nubus-bridge: make slot_available_mask a qdev property
  nubus-bridge: embed the NubusBus object directly within nubus-bridge
  nubus: move NubusBus from mac-nubus-bridge to nubus-bridge
  mac-nubus-bridge: rename MacNubusState to MacNubusBridge
  nubus-bridge: introduce separate NubusBridge structure
  nubus: move nubus to its own 32-bit address space
  nubus-device: add romfile property for loading declaration ROMs
  nubus-device: remove nubus_register_rom() and nubus_register_format_block()
  macfb: don't register declaration ROM
  nubus: generate bus error when attempting to access empty slots
  nubus: add trace-events for empty slot accesses
  nubus: implement BusClass get_dev_path()
  nubus: move slot bitmap checks from NubusDevice realize() to BusClass check_address()
  nubus: use bitmap to manage available slots
  nubus-device: expose separate super slot memory region
  nubus-device: rename slot_nb variable to slot
  nubus: add comment indicating reference documents

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