usb_wwan_indat_callback() shouldn't resubmit rx urb if the previous urb
status is a fatal error. Or the usb controller would keep processing the
new urbs then run into interrupt storm, and has no chance to recover.

Fixes: 6c1ee66a ("USB-Serial: Fix error handling of usb_wwan")
Cc: stable@vger.kernel.org
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Johan Hovold <johan@kernel.org>