net: phy: broadcom: Wire suspend/resume for BCM54612E

The BCM54612E ethernet PHY supports IDDQ-SR.
Therefore wire-up the suspend and resume callbacks
to point to bcm54xx_suspend() and bcm54xx_resume().

Signed-off-by: Marco von Rosenberg <marcovr@selfnet.de>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>