net: sgi: ioc3-eth: Remove leftover free_irq()

Commit 0ce5ebd2 ("mfd: ioc3: Add driver for SGI IOC3 chip") moved
request_irq() from ioc3_open into probe function, but forgot to remove
free_irq() from ioc3_close.

Fixes: 0ce5ebd2 ("mfd: ioc3: Add driver for SGI IOC3 chip")
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>