drm/i915: Factor out hdcp->value assignments

drm/i915: Factor out hdcp->value assignments

This is a bit of housecleaning for a future patch. Instead of sprinkling
hdcp->value assignments and prop_work scheduling everywhere, introduce a
function to do it for us.

Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191203173638.94919-7-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20191212190230.188505-7-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20200117193103.156821-7-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20200218220242.107265-7-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20200305201236.152307-7-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20200429195502.39919-7-sean@poorly.run
Link: https://patchwork.freedesktop.org/patch/msgid/20200623155907.22961-7-sean@poorly.run
Changes in v2:
-None
Changes in v3:
-None
Changes in v4:
-Rebased on top of drm_* logging changes
Changes in v5:
-Change WARN_ON to drm_WARN_ON
Changes in v6:
-None
Changes in v7:
-None
Changes in v8:
-None

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200818153910.27894-7-sean@poorly.run