drm/i915: Factor out HDCP shim functions from dp for use by dp_mst

These functions are all the same for dp and dp_mst, so move them into a
dedicated file for both sst and mst to use.
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191203173638.94919-11-sean@poorly.run #v1
Link: https://patchwork.freedesktop.org/patch/msgid/20191212190230.188505-12-sean@poorly.run #v2
Link: https://patchwork.freedesktop.org/patch/msgid/20200117193103.156821-12-sean@poorly.run #v3
Link: https://patchwork.freedesktop.org/patch/msgid/20200218220242.107265-12-sean@poorly.run #v4
Link: https://patchwork.freedesktop.org/patch/msgid/20200305201236.152307-12-sean@poorly.run #v5
Link: https://patchwork.freedesktop.org/patch/msgid/20200429195502.39919-12-sean@poorly.run #v6
Link: https://patchwork.freedesktop.org/patch/msgid/20200623155907.22961-13-sean@poorly.run #v7

Changes in v2:
-None
Changes in v3:
-Created intel_dp_hdcp.c for the shared functions to live (Ville)
Changes in v4:
-Rebased on new drm logging change
Changes in v5:
-None
Changes in v6:
-None
Changes in v7:
-Rebased patch
Changes in v8:
-None
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200818153910.27894-13-sean@poorly.run

drivers/gpu/drm/i915/Makefile

@@ -234,6 +234,7 @@ i915-y += \
 	display/intel_ddi.o \
 	display/intel_dp.o \
 	display/intel_dp_aux_backlight.o \
+	display/intel_dp_hdcp.o \
 	display/intel_dp_link_training.o \
 	display/intel_dp_mst.o \
 	display/intel_dsi.o \

drivers/gpu/drm/i915/display/intel_dp.h

@@ -136,4 +136,7 @@ void intel_ddi_update_pipe(struct intel_atomic_state *state,
 			   const struct intel_crtc_state *crtc_state,
 			   const struct drm_connector_state *conn_state);
 
+int intel_dp_init_hdcp(struct intel_digital_port *dig_port,
+		       struct intel_connector *intel_connector);
+
 #endif /* __INTEL_DP_H__ */