drm/i915: pass the vma to insert_entries

drm/i915: pass the vma to insert_entries

The vma already contains most of the information we need for insertion.
But also in preparation for supporting huge gtt pages, it would be
useful to know the details of the vma, such that we can we can easily
determine the page sizes we are allowed to use when inserting into the
48b PPGTT.  This is especially true for 64K where we can't just
arbitrarily use it, since we require aligning/padding the vm space to
2M, which sometimes we can't enforce in the upper levels.

Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170622095836.6800-1-matthew.auld@intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>