USB: serial: Enable USB autosuspend by default on qcserial

Seems to work fine in my testing.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c
index cde67ca..2846ad8 100644
--- a/drivers/usb/serial/qcserial.c
+++ b/drivers/usb/serial/qcserial.c
@@ -118,6 +118,8 @@
 
 	spin_lock_init(&data->susp_lock);
 
+	usb_enable_autosuspend(serial->dev);
+
 	switch (nintf) {
 	case 1:
 		/* QDL mode */