This patch removes some more typedefs from usbvideo and related files

typedef struct { .. } RingQueue_t -> struct RingQueue
typedef struct { .. } usbvideo_sbuf_t -> struct usbvideo_sbuf
typedef struct { .. } usbvideo_frame_t -> struct usbvideo_frame
typedef struct { .. } usbvideo_statistics_t -> struct usbvideo_statistics
typedef struct { .. } usbvideo_cb_t -> struct usbvideo_cb