This patch also does a certain amount of rejigging for loop
restoration coefficients, grouping the information for a given
restoration unit into a structure called RestorationUnitInfo. The end
result is to completely dispense with the RestorationInternal
structure.

The copy_tile functions in restoration.c, together with those
functions that operate on a single stripe, have been changed so that
they take pointers to the top-left corner of the area on which they
should work, together with a width and height.

The same isn't true of av1_loop_restoration_filter_unit, which still
takes pointers to the top-left of the tile. This is because you
actually need the absolute position in the tile in order to do striped
loop restoration properly.

Change-Id: I768c182cd15c9b2d6cfabb5ffca697cd2a3ff9e1