fsl/fman: Fix refcount handling of fman-related devices

In mac_probe() there are multiple calls to of_find_device_by_node(),
fman_bind() and fman_port_bind() which takes references to of_dev->dev.
Not all references taken by these calls are released later on error path
in mac_probe() and in mac_remove() which lead to reference leaks.

Add references release.

Fixes: 39339616 ("fsl/fman: Add FMan MAC driver")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>