Revert "drm/i915/tgl: Include ro parts of l3 to invalidate"

This reverts commit 62037fff

.

L3 ro cache invalidation is part of the dword0 of pipe
control. Also it is not relevant to this gen.

Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200506144734.29297-1-mika.kuoppala@linux.intel.com