Do not skip special GGTT views when considering whether an object
is pinned or not.

Wrong behaviour was introduced in;

commit ec7adb6e
Author: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Date:   Mon Mar 16 14:11:13 2015 +0200

    drm/i915: Do not use ggtt_view with (aliasing) PPGTT

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>