[ACPI] on SCI allocation failure, don't mistakenly free IRQ0

	from Jes Sorensen

drivers/acpi/osl.c

@@ -258,13 +258,13 @@ acpi_os_install_interrupt_handler(u32 irq, OSD_HANDLER handler, void *context)
 		return AE_OK;
 	}
 #endif
-	acpi_irq_irq = irq;
 	acpi_irq_handler = handler;
 	acpi_irq_context = context;
 	if (request_irq(irq, acpi_irq, SA_SHIRQ, "acpi", acpi_irq)) {
 		printk(KERN_ERR PREFIX "SCI (IRQ%d) allocation failed\n", irq);
 		return AE_NOT_ACQUIRED;
 	}
+	acpi_irq_irq = irq;
 
 	return AE_OK;
 }
@@ -272,12 +272,13 @@ acpi_os_install_interrupt_handler(u32 irq, OSD_HANDLER handler, void *context)
 acpi_status
 acpi_os_remove_interrupt_handler(u32 irq, OSD_HANDLER handler)
 {
-	if (acpi_irq_handler) {
+	if (irq) {
 #ifdef CONFIG_IA64
 		irq = acpi_irq_to_vector(irq);
 #endif
 		free_irq(irq, acpi_irq);
 		acpi_irq_handler = NULL;
+		acpi_irq_irq = 0;
 	}
 
 	return AE_OK;