acpi-wmi: unsigned cannot be less than 0

include/linux/pci-acpi.h:74:

typedef u32                 acpi_status;

result is unsigned, so an error returned by acpi_bus_register_driver()
will not be noticed.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/platform/x86/wmi.c

@@ -708,7 +708,7 @@ static int __init acpi_wmi_add(struct acpi_device *device)
 
 static int __init acpi_wmi_init(void)
 {
-	acpi_status result;
+	int result;
 
 	INIT_LIST_HEAD(&wmi_blocks.list);