net: davicom: Fix regulator not turned off on failed probe

When the probe fails, we must disable the regulator that was previously
enabled.

This patch is a follow-up to commit ac88c531
("net: davicom: Fix regulator not turned off on failed probe") which missed
one case.

Fixes: 7994fe55

 ("dm9000: Add regulator and reset support to dm9000")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>