drm/i915: Attach content type property

drm/i915: Attach content type property

Attaches the content type property for HDCP2.2 capable connectors.

Implements the update of content type from property and apply the
restriction on HDCP version selection.

Need ACK for content type property from userspace consumer.

v2:
  s/cp_content_type/content_protection_type [daniel]
  disable at hdcp_atomic_check to avoid check at atomic_set_property
	[Maarten]
v3:
  s/content_protection_type/hdcp_content_type [Pekka]
v4:
  hdcp disable incase of type change is moved into commit [daniel].
v5:
  Simplified the Type change procedure. [Daniel]
v6:
  Type change with UNDESIRED state is ignored.

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/320959/?series=57232&rev=14