dma_buf: remove device parameter from attach callback v2

The device parameter is completely unused because it is available in the
attachment structure as well.

v2: fix kerneldoc as well

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/226643/