drm/i915/hdcp: Add new remote capability check shim function

Create a remote HDCP capability shim function which can read the
remote monitor HDCP capability when in MST configuration.

--v2
-Add an assertion to make sure only mst encoder call this remote_cap
function [Ankit]

--v3
-rename remote_hdcp_cap to remote_hdcp_capability [Jani]

--v4
-fix hdcp2_prerequisite check condition
-Move intel_dp_hdcp_get_remote_capability to dp_mst shim instead of
having it in dp shim [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/20240226051017.1652970-2-suraj.kandpal@intel.com