drivers/atm/eni.c: ensure arguments to request_irq and free_irq are compatible

Convert calls to free_irq so that the second argument is the same as the
last argument of the corresponding call to request_irq.  Without this
property, free_irq does nothing.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>