net: phy: Propagate error from bus->reset

If a bus->reset() call for the mii_bus structure returns an error (e.g.:
-EPROE_DEFER) we should propagate it accordingly.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>