drm/i915/hdcp: Fix the return handling of drm_hdcp_check_ksvs_revoked

drm_hdcp_check_ksvs_revoked() returns the number of revoked keys and
error codes when the SRM parsing is failed.

Errors in SRM parsing can't affect the HDCP auth, hence with this patch,
I915 will look out for revoked key count alone.
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
cc: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429134555.22106-1-ramalingam.c@intel.com

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

@@ -576,7 +576,7 @@ int intel_hdcp_auth_downstream(struct intel_connector *connector)
 		goto err;
 
 	if (drm_hdcp_check_ksvs_revoked(&dev_priv->drm, ksv_fifo,
-					num_downstream)) {
+					num_downstream) > 0) {
 		drm_err(&dev_priv->drm, "Revoked Ksv(s) in ksv_fifo\n");
 		ret = -EPERM;
 		goto err;
@@ -682,7 +682,7 @@ static int intel_hdcp_auth(struct intel_connector *connector)
 	if (ret < 0)
 		return ret;
 
-	if (drm_hdcp_check_ksvs_revoked(&dev_priv->drm, bksv.shim, 1)) {
+	if (drm_hdcp_check_ksvs_revoked(&dev_priv->drm, bksv.shim, 1) > 0) {
 		drm_err(&dev_priv->drm, "BKSV is revoked\n");
 		return -EPERM;
 	}
@@ -1283,7 +1283,7 @@ static int hdcp2_authentication_key_exchange(struct intel_connector *connector)
 
 	if (drm_hdcp_check_ksvs_revoked(&dev_priv->drm,
 					msgs.send_cert.cert_rx.receiver_id,
-					1)) {
+					1) > 0) {
 		drm_err(&dev_priv->drm, "Receiver ID is revoked\n");
 		return -EPERM;
 	}
@@ -1484,7 +1484,7 @@ int hdcp2_authenticate_repeater_topology(struct intel_connector *connector)
 		      HDCP_2_2_DEV_COUNT_LO(rx_info[1]));
 	if (drm_hdcp_check_ksvs_revoked(&dev_priv->drm,
 					msgs.recvid_list.receiver_ids,
-					device_cnt)) {
+					device_cnt) > 0) {
 		drm_err(&dev_priv->drm, "Revoked receiver ID(s) is in list\n");
 		return -EPERM;
 	}