fsl/fman: Remove some useless code

There is no need to release explicitly some devm_ allocated resources.
If the 'mac_probe()' probe function fails, they will be released
automatically, as already done in the other error handling paths of
this function.

Also goto '_return_of_get_parent' as in the other error handling paths.
This is useless (priv->fixed_link is NULL at this point), but at least
it is consistent.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>