MFC r354291 - r354322, r354327, r355596

r354291:
[ig4] Give common name to PCI and ACPI device drivers

r354292:
[ig4] Handle controller startup errors

Obtained from: DragonflyBSD (509820b)

r354293:
[ig4] Only enable interrupts when we want them. Otherwise keep mask at 0.

Obtained from: DragonflyBSD (d7c8555)

r354294:
[ig4] Drop driver's internal RX FIFO

r354295:
[ig4] Do not wait for interrupts in set_controller() routine

r354296:
[ig4] Reduce scope of io_lock

r354297:
[ig4] Ignore stray interrupts

r354298:
[ig4] We actually need to set the Rx threshold register one smaller.

Obtained from: DragonflyBSD (02f0bf2)

r354299:

[ig4] Stop I2C controller after checking that it's kind of functional.

Obtained from: DragonfliBSD (0b3eedb)

r354300:
[ig4] disable controller before initialization of clock counters

r354301:
[ig4] Add support for polled mode

r354302:
[ig4] Allow enabling of polled mode from iicbus allocation callback

r354303:
[ig4] Do not wait until interrupts are enabled at attach stage

r354304:
[cyapa] Postpone start of the polling thread until sleep is available

r354305:
[ig4] dump IG4_REG_COMP_PARAM1 and IG4_REG_COMP_VER registers unconditionally

r354306:
[ig4] Set clock registers based on controller model

r354307:
[ig4] Implement burst mode for data reads

r354308:
[ig4] Add suspend/resume support

PR: 238037

r354309:
[ig4] Remove dead code inherited from DragonflyBSD

r354310:
[ig4] Rewrite ig4iic_write routine to use TX_EMPTY status flag

r354311:
[ig4] Convert last remaining usage of TX_NOTFULL status to TX_EMPTY

r354312:
[ig4] Use interrupts for waiting for empty TX FIFO

r354313:
[ig4] Convert polling loop from status-based to interrupt-based

r354314:
[ig4] Improve error detection

r354315:
[ig4] Set STOP condition and flush TX/RX FIFOs on error

r354316:
[ig4] On SkyLake controllers issue reset on attach unconditionally.

r354317:
[ig4] wait for bus stop condition after stop command issued

r354318:
[ig4] Minor improvement of write pipelining

r354319:
[ig4] Add generic resource methods to bus interface

r354320:
[ig4] Add support for CannonLake controllers

PR: 240485
Submitted by: Neel Chauhan <neel@neelc.org>

r354321:
[ig4] Enable additional registers support on Appolo Lake controllers

r354322:
[ig4] Convert ithread interrupt handler to filter based one.

r354327:
[ig4] Try to workaround MIPS namespace pollution issue

r355596:
[ig4] Remove unused methods from bus interface

Suggested by: jhb

Reviewed by: imp (previous version)
Differential Revision: https://reviews.freebsd.org/D22016