[Coverity 1666263] Infinite loop in h264_parse_picture_parameter_set_rbsp

The loop does not have a normal termination condition, so will continue until an abnormal condition arises.

In h264_parse_picture_parameter_set_rbsp: Infinite loop with unsatisfiable exit condition (CWE-835)

      CID 1666263: (#1 of 1): Infinite loop (INFINITE_LOOP)
      loop_top: Top of the loop.
      loop_condition: If num_slice_groups > 1U is initially true then it will remain true.
594            while(num_slice_groups > 1)
595            {
596                sliceGroupSize++;
      non_progress_update: Update num_slice_groups = (num_slice_groups - 1U >> 1) + 1U makes no progress toward falsifying the loop condition num_slice_groups > 1U.
597                num_slice_groups = ((num_slice_groups - 1) >> 1) + 1;
      loop_bottom: Bottom of the loop.
598            }