mei: abort waiting for notification on unsupported HW

On legacy HW, pre Skylake, the notifications are not supported,
return -EOPNOTSUPP in mei_cl_notify_get and prevent
waiting indefinitely.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/client.c

@@ -1428,6 +1428,11 @@ int mei_cl_notify_get(struct mei_cl *cl, bool block, bool *notify_ev)
 
 	dev = cl->dev;
 
+	if (!dev->hbm_f_ev_supported) {
+		cl_dbg(dev, cl, "notifications not supported\n");
+		return -EOPNOTSUPP;
+	}
+
 	if (!mei_cl_is_connected(cl))
 		return -ENODEV;