* Inline constrain and msb for cdef_filter_block
  This reduces its average time by around 42%.
* Inline round_shift for pred_directional and others
  This reduces its average time by around 10%.
* Inline sgrproj_sum_finish to its various callers
  It is at the lowest level of a hot call graph and almost trivial.
* Inline get_mv_rate in motion estimation
  It is almost trivial and called often.