max_tile was provisionally adopted at the working group meeting 2017-Oct-10

This patch also enables support for 64x64 and 128x128 superblock size for max tile
(rather than assuming 128). There is also one fix for max_tile in combination of
loop restoration where the width/height was in the wrong units for max-tile specific code.

Change-Id: Icb862a2738fea5fc6215819396e1afa4eb86e461