Revert "i965/gen9: Plugin the code for selecting YF/YS tiling on skl+"

Revert "i965/gen9: Plugin the code for selecting YF/YS tiling on skl+"

Commit c9dbdc0 introduced some dead code which is supposed to be used
once we have Yf/Ys tiling working and performing better. Ken reported
the issue that static analysis tool now shows warnings due to the dead
code. To fix these warnings, this patch reverts the changes made in
commit c9dbdc0.

It'll be better to add the Yf/Ys tiling selection code later, when we
are ready to use it.

Signed-off-by: Anuj Phogat <anuj.phogat@gmail.com>
Acked-by: Kenneth Graunke <kenneth@whitecape.org>