netxen: fix tx timeout recovery for NX2031 chip

For NX2031, first try to scrub interrupt before requesting firmware
reset. Return statement was missing after scrubbbing interrupt.

Signed-off-by: Vernon Mauery <vernux@us.ibm.com>
Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>