net: smsc911x: Reset PHY during initialization

On certain hardware after software reboot the chip may get stuck and fail
to reinitialize during reset. This can be fixed by ensuring that PHY is
reset too.

Old PHY resetting method required operational MDIO interface, therefore
the chip should have been already set up. In order to be able to function
during probe, it is changed to use PMT_CTRL register.

The problem could be observed on SMDK5410 board.

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>