net: ethernet: cpsw: drop IRQF_DISABLED

IRQF_DISABLED is a no-op by now and should be
removed.

Signed-off-by: Felipe Balbi <balbi@ti.com>
Acked-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>