Since commit 058d88c4 ("drm/i915: Track pinned VMA"), there is only
one user of i915_ggtt_view_normal rodate. Just treat NULL as no special
view in pin_to_display() like everywhere else.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170114002827.31315-7-chris@chris-wilson.co.uk