UPSTREAM: dma-buf/fence: add an lockdep_assert_held()

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1477339030-32657-1-git-send-email-robdclark@gmail.com


(cherry picked from commit 78010cd9736ec571796f4404524ed575b81238b9)
Signed-off-by: Marissa Wall <marissaw@google.com>

Change-Id: I8fce7abb30f9f54e87deab215556f3679c6afa1e