media: videobuf2-core: clear memory related fields in __vb2_plane_dmabuf_put()

[ Upstream commit 6a9c97ab6b7e85697e0b74e86062192a5ffffd99 ]

Clear vb2_plane's memory related fields in __vb2_plane_dmabuf_put(),
including bytesused, length, fd and data_offset.

Remove the duplicated code in __prepare_dmabuf().

Signed-off-by: Yunke Cao <yunkec@chromium.org>
Acked-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>