[IA64] genirq fixup for SGI/SN

This patch allows the system to boot and enables the console and at least
some hardware drivers, as well as some platform error handling.

Tested on a variety of SGI Altix system without issues.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Tested-by: Raymund Will <rw@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>

drivers/tty/serial/sn_console.c

@@ -743,6 +743,7 @@ static void __init sn_sal_switch_to_interrupts(struct sn_cons_port *port)
 			spin_lock_irqsave(&port->sc_port.lock, flags);
 			port->sc_port.irq = SGI_UART_VECTOR;
 			port->sc_ops = &intr_ops;
+			irq_set_handler(port->sc_port.irq, handle_level_irq);
 
 			/* turn on receive interrupts */
 			ia64_sn_console_intr_enable(SAL_CONSOLE_INTR_RECV);