Division by zero in uvc_drv_try_frame_interval for continuous-interval frames (bFrameIntervalType==0)

Summary

For VS frame descriptors with bFrameIntervalType==0 (continuous intervals) uvc_drv_parse_data skips 3 interval slots (itv+=3) WITHOUT reading dFrameInterval[0..2] min/max/step DWORDs. Slots stay zero (M_ZERO allocation). uvc_drv_try_frame_interval continuous branch divides by step==frame->interval[2].val==0 kernel panic. Any local user triggers via VIDIOC_TRY_FMT/S_FMT/S_PARM on /dev/video0 (mode 0666). Two coupled bugs: parse skips reading DWORDs + try_frame_interval no zero-step guard. Deterministic local DoS.