Convert cpmac to new napi_struct API introduced by bea3348eef27e6044b6161fd04c3152215f96411 [NET]: Make NAPI polling independent
of struct net_device objects.
Only disable rx interrupts if napi actually has been scheduled.
Signed-off-by: Eugene Konev <ejka@imfi.kspu.ru> Signed-off-by: Jeff Garzik <jeff@garzik.org>