drm/v3d: Remove unnecessary dma_fence_ops.

The dma-fence core as of commit 418cc6ca ("dma-fence: Make ->wait
callback optional") provides appropriate defaults for these methods.

Signed-off-by: Eric Anholt <eric@anholt.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180703170515.6298-2-eric@anholt.net


Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>