drm/i915/hdcp: MST streams support in hdcp port_data

Add support for multiple mst stream in hdcp port data
which will be used by RepeaterAuthStreamManage msg and
HDCP 2.2 security f/w for m' validation.

Security f/w doesn't have any provision to mark the stream_type
for each stream separately, it just take single input of
stream_type while authenticating the port and applies the
same stream_type to all streams. So driver mark each stream_type
with common highest supported content type for all streams
in DP MST Topology.

Security f/w supports RepeaterAuthStreamManage msg and m'
validation only once during port authentication and encryption.
Though it is not compulsory, security fw should support dynamic
update of content_type and should support RepeaterAuthStreamManage
msg and m' validation whenever required.

v2:
- Init the hdcp port data k for HDMI/DP SST stream.
v3:
- Cosmetic changes. [Uma]
v4:
- 's/port_auth/hdcp_port_auth'. [Ram]
- Commit log improvement.
v5:
- Comment and commit log improvement. [Ram]
v6:
- Check first connector connected status before intel_encoder_is_mst
  to avoid any NULL pointer dereference.

Cc: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Tested-by: Karthik B S <karthik.b.s@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Tested-by: Juston Li <juston.li@intel.com>
Acked-by: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210111081120.28417-15-anshuman.gupta@intel.com