usb: dwc2: Remove unnecessary request length checking

Remove request length checking from dwc2_hsotg_unmap_dma() and
dwc2_hsotg_map_dma(). That checking is done in functions called from
those functions, usb_gadget_unmap_request_by_dev() and
usb_gadget_map_request_by_dev() respectively, so it's unnecessary.

Signed-off-by: Razmik Karapetyan <razmik@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>