drm/i915: Implement HDCP2.2 link integrity check

drm/i915: Implement HDCP2.2 link integrity check

Implements the link integrity check once in 500mSec.

Once encryption is enabled, an ongoing Link Integrity Check is
performed by the HDCP Receiver to check that cipher synchronization
is maintained between the HDCP Transmitter and the HDCP Receiver.

On the detection of synchronization lost, the HDCP Receiver must assert
the corresponding bits of the RxStatus register. The Transmitter polls
the RxStatus register and it may initiate re-authentication.

v2:
  Rebased.
v3:
  enum check_link_response is used check the link status [Uma]
v4:
  Rebased as part of patch reordering.
v5:
  Required members of intel_hdcp is defined [Sean Paul]
v6:
  hdcp2_check_link is cancelled at required places.
v7:
  Rebased for the component i/f changes.
  Errors due to the sinks are reported as DEBUG logs.
v8:
  hdcp_check_work is used for both hdcp1 and hdcp2 check_link [Daniel]
  hdcp2.2 encryption status check is put under WARN_ON [Daniel]
  drm_hdcp.h changes are moved into separate patch [Daniel]
v9:
  enum check_link_status is defined at intel_drv.h [Daniel]

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1550338640-17470-11-git-send-email-ramalingam.c@intel.com