smsc95xx: avoid memory leak in smsc95xx_bind

In a case where the ID_REV register read is failed, the memory for a
private data structure has to be freed before returning error from the
function smsc95xx_bind.

Fixes: bbd9f9ee ("smsc95xx: add wol support for more frame types")
Signed-off-by: Andre Edich <andre.edich@microchip.com>
Signed-off-by: Parthiban Veerasooran <Parthiban.Veerasooran@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>