Update filter_selectively_vert_row2()
Update filter_selectively_vert_row2()

Reduce operations and jumps. perf shows CPU time reduced from 1.9% to
1.6% when decoding fdJc1_IBKJA.248.webm on Xeon E5.
Will apply the changes to vp10 after code review.

Change-Id: I9351509922855d8896ddef1ed093b3ca12619a61

Topopiccione/libvpx,GrokImageCompression/aom,luctrudeau/aom,mwgoldsmith/vpx,mbebenita/aom,GrokImageCompression/aom,luctrudeau/aom,webmproject/libvpx,mbebenita/aom,webmproject/libvpx,ShiftMediaProject/libvpx,GrokImageCompression/aom,GrokImageCompression/aom,mbebenita/aom,mwgoldsmith/vpx,smarter/aom,ShiftMediaProject/libvpx,smarter/aom,GrokImageCompression/aom,webmproject/libvpx,Topopiccione/libvpx,mbebenita/aom,smarter/aom,mwgoldsmith/vpx,mwgoldsmith/vpx,mwgoldsmith/vpx,GrokImageCompression/aom,mbebenita/aom,smarter/aom,ShiftMediaProject/libvpx,mbebenita/aom,mbebenita/aom,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,luctrudeau/aom,smarter/aom,Topopiccione/libvpx,mwgoldsmith/libvpx,mwgoldsmith/libvpx,mwgoldsmith/libvpx,luctrudeau/aom,mwgoldsmith/vpx,mwgoldsmith/libvpx,mbebenita/aom,mwgoldsmith/libvpx,Topopiccione/libvpx,luctrudeau/aom,Topopiccione/libvpx,mwgoldsmith/libvpx,ShiftMediaProject/libvpx,Topopiccione/libvpx,smarter/aom,mbebenita/aom,luctrudeau/aom,ShiftMediaProject/libvpx