[PATCH] s2io build fix

sparc32:

drivers/net/s2io.c:2636: warning: implicit declaration of function 'disable_irq'
drivers/net/s2io.c:2656: warning: implicit declaration of function 'enable_irq'

Cc: Ananda Raju <Ananda.Raju@neterion.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>