drm/i915/hdcp: Use correct cp_irq_count

We are checking cp_irq_count from the wrong hdcp structure which
ends up giving timed out errors. We only increment the cp_irq_count
of the primary connector's hdcp structure but here in case of
multidisplay setup we end up checking the secondary connector's hdcp
structure, which will not have its cp_irq_count incremented. This leads
to a timed out at CP_IRQ error even though a CP_IRQ was raised. Extract
it from the correct intel_hdcp structure.

--v2
-Explain why it was the wrong hdcp structure [Jani]

Fixes: 8c9e4f6 ("drm/i915/hdcp: Use per-device debugs")
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240809114127.3940699-2-suraj.kandpal@intel.com
(cherry picked from commit dd92590)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/display/intel_dp_hdcp.c

@@ -39,7 +39,9 @@ static u32 transcoder_to_stream_enc_status(enum transcoder cpu_transcoder)
 static void intel_dp_hdcp_wait_for_cp_irq(struct intel_connector *connector,
 					  int timeout)
 {
-	struct intel_hdcp *hdcp = &connector->hdcp;
+	struct intel_digital_port *dig_port = intel_attached_dig_port(connector);
+	struct intel_dp *dp = &dig_port->dp;
+	struct intel_hdcp *hdcp = &dp->attached_connector->hdcp;
 	long ret;
 
 #define C (hdcp->cp_irq_count_cached != atomic_read(&hdcp->cp_irq_count))