NULL noise: drivers/platform/x86/panasonic-laptop.c

Fix this sparse warning:
  drivers/platform/x86/panasonic-laptop.c:273:70: warning: Using plain integer as NULL pointer

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/platform/x86/panasonic-laptop.c b/drivers/platform/x86/panasonic-laptop.c
index a5ce4bc..41cf3e7 100644
--- a/drivers/platform/x86/panasonic-laptop.c
+++ b/drivers/platform/x86/panasonic-laptop.c
@@ -271,7 +271,7 @@
 	union acpi_object *hkey = NULL;
 	int i;
 
-	status = acpi_evaluate_object(pcc->handle, METHOD_HKEY_SINF, 0,
+	status = acpi_evaluate_object(pcc->handle, METHOD_HKEY_SINF, NULL,
 				      &buffer);
 	if (ACPI_FAILURE(status)) {
 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,