drm/mst: Add support for QUERY_STREAM_ENCRYPTION_STATUS MST sideband message

drm/mst: Add support for QUERY_STREAM_ENCRYPTION_STATUS MST sideband message

Used to query whether an MST stream is encrypted or not.

Cc: Lyude Paul <lyude@redhat.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200218220242.107265-14-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20200305201236.152307-15-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20200429195502.39919-15-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20200623155907.22961-16-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20200818153910.27894-16-sean@poorly.run
Changes in v4:
-Added to the set
Changes in v5:
-None
Changes in v6:
-Use FIELD_PREP to generate request buffer bitfields (Lyude)
-Add mst selftest and dump/decode_sideband_req for QSES (Lyude)
Changes in v7:
-None
Changes in v8:
-Reverse the parsing on the hdcp_*x_device_present bits and leave
 breadcrumb in case this is incorrect (Anshuman)
Changes in v8.5:
-s/DRM_DEBUG_KMS/drm_dbg_kms/ (Lyude)

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200819143133.46232-1-sean@poorly.run