usb: gadget: uvc: remove references to DMA_ADDR_INVALID

gadget drivers shouldn't touch req->dma at all,
since UDC drivers are the ones required to handle
mapping and unmapping of the request buffer.

Remove references to DMA_ADDR_INVALID so we don't
creat false expectations to gadget driver writers.
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/uvc.h

@@ -98,8 +98,6 @@ extern unsigned int uvc_gadget_trace_param;
 #define DRIVER_VERSION				"0.1.0"
 #define DRIVER_VERSION_NUMBER			KERNEL_VERSION(0, 1, 0)
 
-#define DMA_ADDR_INVALID			(~(dma_addr_t)0)
-
 #define UVC_NUM_REQUESTS			4
 #define UVC_MAX_REQUEST_SIZE			64
 #define UVC_MAX_EVENTS				4

drivers/usb/gadget/uvc_v4l2.c

@@ -41,7 +41,6 @@ uvc_send_response(struct uvc_device *uvc, struct uvc_request_data *data)
 
 	req->length = min_t(unsigned int, uvc->event_length, data->length);
 	req->zero = data->length < uvc->event_length;
-	req->dma = DMA_ADDR_INVALID;
 
 	memcpy(req->buf, data->data, data->length);
 

drivers/usb/gadget/uvc_video.c

@@ -245,7 +245,6 @@ uvc_video_alloc_requests(struct uvc_video *video)
 
 		video->req[i]->buf = video->req_buffer[i];
 		video->req[i]->length = 0;
-		video->req[i]->dma = DMA_ADDR_INVALID;
 		video->req[i]->complete = uvc_video_complete;
 		video->req[i]->context = video;