drm/i915: Pass vma to relocate entry

We can simplify our tracking of pending writes in an execbuf to the
single bit in the vma->exec_entry->flags, but that requires the
relocation function knowing the object's vma. Pass it along.

Note we have only been using a single bit to track flushing since

commit cc889e0f
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed Jun 13 20:45:19 2012 +0200

    drm/i915: disable flushing_list/gpu_write_list

unconditionally flushed all render caches before the breadcrumb and

commit 6ac42f41
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Sat Jul 21 12:25:01 2012 +0200

    drm/i915: Replace the complex flushing logic with simple invalidate/flush all

did away with the explicit GPU domain tracking. This was then codified
into the ABI with NO_RELOC in

commit ed5982e6


Author: Daniel Vetter <daniel.vetter@ffwll.ch> # Oi! Patch stealer!
Date:   Thu Jan 17 22:23:36 2013 +0100

    drm/i915: Allow userspace to hint that the relocations were known

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>