Indicate if gadget driver must use dma for usb transfers.
Tested-by: NRobert Baldyga <r.baldyga@samsung.com>
Acked-by: NPaul Zimmerman <paulz@synopsys.com>
Signed-off-by: NGregory Herrero <gregory.herrero@intel.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>