media: v4l2-mem2mem: Fix spurious v4l2_m2m_buf_done

A seemingly bad rebase introduced a spurious v4l2_m2m_buf_done,
which releases a buffer twice and therefore triggers a
noisy warning on each job:

WARNING: CPU: 0 PID: 0 at drivers/media/common/videobuf2/videobuf2-core.c:986 vb2_buffer_done+0x208/0x2a0

Fix it by removing the spurious v4l2_m2m_buf_done.

Reported-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Fixes: 911ea8ec ("media: v4l2-mem2mem: add v4l2_m2m_suspend, v4l2_m2m_resume")
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Tested-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>