ata: pata_octeon_cf: Fix refcount leak in octeon_cf_probe

of_find_device_by_node() takes reference, we should use put_device()
to release it when not need anymore.
Add missing put_device() to avoid refcount leak.

Fixes: 43f01da0

 ("MIPS/OCTEON/ata: Convert pata_octeon_cf.c to use device tree.")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>