drm/i915/icl: Interrupt handling

drm/i915/icl: Interrupt handling

v2: Rebase.

v3:
  * Remove DPF, it has been removed from SKL+.
  * Fix -internal rebase wrt. execlists interrupt handling.

v4: Rebase.

v5:
  * Updated for POR changes. (Daniele Ceraolo Spurio)
  * Merged with irq handling fixes by Daniele Ceraolo Spurio:
      * Simplify the code by using gen8_cs_irq_handler.
      * Fix interrupt handling for the upstream kernel.

v6:
  * Remove early bringup debug messages (Tvrtko)
  * Add NB about arbitrary spin wait timeout (Tvrtko)

v7 (from Paulo):
  * Don't try to write RO bits to registers.
  * Don't check for PCH types that don't exist. PCH interrupts are not
    here yet.

v9:
  * squashed in selector and shared register handling (Daniele)
  * skip writing of irq if data is not valid (Daniele)
  * use time_after32 (Chris)
  * use I915_MAX_VCS and I915_MAX_VECS (Daniele)
  * remove fake pm interrupt handling for later patch (Mika)

v10:
  * Direct processing of banks. clear banks early (Chris)
  * remove poll on valid bit, only clear valid bit (Mika)
  * use raw accessors, better naming (Chris)

v11:
  * adapt to raw_reg_[read|write]
  * bring back polling the valid bit (Daniele)

v12:
  * continue if unset intr_dw (Daniele)
  * comment the usage of gen8_de_irq_handler bits (Daniele)

Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180228101153.7224-2-mika.kuoppala@linux.intel.com