net: phy: smsc: move smsc_phy_config_init reset part in a soft_reset function

On the one hand, phy_device.c provides a generic reset function if the phy
driver does not provide a soft_reset pointer. This generic reset does not take
into account the state of the phy, with a potential failure if the phy is in
powerdown mode. On the other hand, smsc driver provides a function with both
correct reset behaviour and configuration.

This patch moves the reset part into a new smsc_phy_reset function and provides
the soft_reset pointer to have a correct reset behaviour by default.

Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou@armadeus.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>