Fix error in get_ul_intra_threshold() for 10/12 bit.
Fix error in get_ul_intra_threshold() for 10/12 bit.

The scaling of the threshold for 10 and 12 bit here appears
to be in the wrong direction. For 10 and 12 bit we expect sse
values to be higher and hence the threshold used should be
scaled up not down.

Change-Id: I2678116652b539aef48100e0f22873edd4f5a786

webmproject/libvpx,mwgoldsmith/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,mwgoldsmith/libvpx,mwgoldsmith/vpx,mwgoldsmith/vpx,webmproject/libvpx,mwgoldsmith/libvpx,ShiftMediaProject/libvpx,mwgoldsmith/libvpx,Topopiccione/libvpx,ShiftMediaProject/libvpx,mwgoldsmith/vpx,ShiftMediaProject/libvpx,webmproject/libvpx,mwgoldsmith/vpx,Topopiccione/libvpx,Topopiccione/libvpx,mwgoldsmith/libvpx,Topopiccione/libvpx,mwgoldsmith/libvpx,mwgoldsmith/vpx,mwgoldsmith/vpx,ShiftMediaProject/libvpx,webmproject/libvpx,Topopiccione/libvpx,Topopiccione/libvpx,webmproject/libvpx