net: bcmgenet: power down internal phy if open or resume fails

Since the internal PHY is powered up during the open and resume
functions it should be powered back down if the functions fail.

Fixes: 1c1008c7

 ("net: bcmgenet: add main driver file")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>