net: natsemi: remove deprecated IRQF_DISABLED

This patch proposes to remove the IRQF_DISABLED flag from
code in drivers/net/ethernet/natsemi/

It's a NOOP since 2.6.35 and it will be removed one day.

Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>