firmware: arm_scmi: Clear channel for delayed responses

Clear channel properly when done processing a delayed response.
This will let the platform firmware know that the channel is now free to
use it for any new delayed response or notification.

Link: https://lore.kernel.org/r/20200420152315.21008-4-cristian.marussi@arm.com
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
(sudeep.holla: Updated commit log to reflect that channel is now free for
 platform to use)
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/driver.c

@@ -256,10 +256,12 @@ static void scmi_handle_response(struct scmi_chan_info *cinfo,
 			   xfer->hdr.protocol_id, xfer->hdr.seq,
 			   msg_type);
 
-	if (msg_type == MSG_TYPE_DELAYED_RESP)
+	if (msg_type == MSG_TYPE_DELAYED_RESP) {
+		info->desc->ops->clear_channel(cinfo);
 		complete(xfer->async_done);
-	else
+	} else {
 		complete(&xfer->done);
+	}
 }
 
 /**