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

q800 pull request 20210908

mac_via: remove MAC_VIA device and prepare for Nubus IRQs

# gpg: Signature made Wed 08 Sep 2021 16:35:03 BST
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "[email protected]"
# gpg: Good signature from "Laurent Vivier <[email protected]>" [full]
# gpg:                 aka "Laurent Vivier <[email protected]>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <[email protected]>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier/tags/q800-pull-request:
  mac_via: add qdev gpios for nubus slot interrupts to VIA2
  mac_via: rename VIA2_IRQ_SLOT_BIT to VIA2_IRQ_NUBUS_BIT
  mac_via: remove explicit viaN prefix from VIA IRQ gpios
  mac_via: remove mac_via device
  mac_via: move VIA1 realize logic from mac_via_realize() to mos6522_q800_via1_realize()
  mac_via: move VIA1 reset logic from mac_via_reset() to mos6522_q800_via1_reset()
  mac_via: move q800 VIA1 timer variables to q800 VIA1 VMStateDescription
  mac_via: move ADB variables to MOS6522Q800VIA1State
  mac_via: move PRAM/RTC variables to MOS6522Q800VIA1State
  mac_via: move PRAM contents and block backend to MOS6522Q800VIA1State
  mac_via: move last_b variable into q800 VIA1 VMStateDescription
  mac_via: introduce new VMStateDescription for q800 VIA1 and VIA2

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