[media] m2m-deinterlace: don't return zero on failure paths in deinterlace_probe()

If DMA does not support INTERLEAVE, deinterlace_probe() breaks off
initialization, releases dma channel, but returns zero.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>