In preparation for fixing the check for number of remaining TRBs,
revise dwc3_prepare_one_trb_linear() and dwc3_prepare_one_trb_sg() to
return the number of prepared TRBs.
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>