sony-laptop: use NULL for pointer

Use NULL instead of 0 for pointer:
drivers/misc/sony-laptop.c:1920:6: warning: Using plain integer as NULL pointer

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/misc/sony-laptop.c

@@ -1917,7 +1917,8 @@ end:
  */
 static int sony_pic_disable(struct acpi_device *device)
 {
-	if (ACPI_FAILURE(acpi_evaluate_object(device->handle, "_DIS", 0, NULL)))
+	if (ACPI_FAILURE(acpi_evaluate_object(device->handle,
+			"_DIS", NULL, NULL)))
 		return -ENXIO;
 
 	dprintk("Device disabled\n");