[SERIAL] fix PCI interrupt setting for ia64

Patch from Bjorn Helgaas

ACPI and HCDP tell us what IRQ the serial port uses, so there's
no need to have the driver probe for the IRQ.

drivers/serial/8250_acpi.c

@@ -134,8 +134,7 @@ static int acpi_serial_add(struct acpi_device *device)
 	}
 
 	serial_req.baud_base = BASE_BAUD;
-	serial_req.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF |
-			   UPF_AUTO_IRQ  | UPF_RESOURCES;
+	serial_req.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF | UPF_RESOURCES;
 
 	priv->line = register_serial(&serial_req);
 	if (priv->line < 0) {

drivers/serial/8250_hcdp.c

@@ -186,8 +186,6 @@ setup_serial_hcdp(void *tablep)
 		port.irq = gsi;
 #endif
 		port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF | UPF_RESOURCES;
-		if (gsi)
-			port.flags |= ASYNC_AUTO_IRQ;
 
 		/*
 		 * Note: the above memset() initializes port.line to 0,