[media] uvcvideo: Remove duplicate definitions of UVC_STREAM_* macros

The macros are defined in both drivers/media/video/uvc/uvc_video.c and
include/linux/usb/video.h. Remove definitions from the former.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>