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