NET: smc91x: convert to dev_pm_ops

Convert smc91x driver from legacy PM hooks over to using dev_pm_ops.

Tested on OMAP3 platform.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: David S. Miller <davem@davemloft.net>