If we abort the i915_gem_internal get_pages, we mark the failing sg as
the last. However, that means we iterate upto and including the failing
sg element and results in us trying to free the unallocated sg_page().
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170131104630.3074-1-chris@chris-wilson.co.ukReviewed-by: Matthew Auld <matthew.auld@intel.com>