drm/i915: Make intel_pin_and_fence_fb_obj take plane and framebuffer

It will help future code if this function knows something about of the context
of the display setup object is being pinned for.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>