drm/i915/hdcp: HDCP Capability for the downstream device

drm/i915/hdcp: HDCP Capability for the downstream device

Currently we are only checking capability of remote device and not
immediate downstream device but during capability check we need are
concerned with only the HDCP capability of downstream device.
During i915_display_info reporting we need HDCP Capability for both
the monitors and downstream branch device if any this patch adds that.

--v2
-Use MST Hub HDCP version [Ankit]

--v3
-Redefined how we seprate remote and direct read to make sure HDMI
shim functions are not touched [Ankit]

--v4
- Fix the conditions so that hdcp_info with remote_req true is sent
only when encoder is mst [Ankit]

--v5
-No need to have the MST Hub version in i915_hdcp_sink_capability[Ankit]

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240223081453.1576918-9-suraj.kandpal@intel.com