Consistent naming for loop-filter filters.

Renaming flatmask4 to flat_mask4, flatmask5 to flat_mask5, hevmask to
hev_mask, filter to filter4, mbfilter to filter8, wide_mbfilter to
filter16.

Change-Id: Ic61c73e59c2eee505257584867aafac99833cea1
1 file changed