drm/i915: Handle HDCP2.2 downstream topology change

drm/i915: Handle HDCP2.2 downstream topology change

When repeater notifies a downstream topology change, this patch
reauthenticate the repeater alone without disabling the hdcp
encryption. If that fails then complete reauthentication is executed.

v2:
  Rebased.
v3:
  Typo in commit msg is fixed [Uma]
v4:
  Rebased as part of patch reordering.
  Minor style fixes.
v5:
  Rebased.
v6:
  Rebased.
v7:
  Errors due to sinks are reported as DEBUG logs.

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/1550338640-17470-12-git-send-email-ramalingam.c@intel.com