ACPI: dock: use NULL for pointer

Use NULL instead of 0 for pointers:
drivers/acpi/dock.c:677:75: warning: Using plain integer as NULL pointer

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index 811b1aac65d5..4546bf873aea 100644
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -29,6 +29,7 @@
 #include <linux/notifier.h>
 #include <linux/platform_device.h>
 #include <linux/jiffies.h>
+#include <linux/stddef.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 
@@ -674,7 +675,7 @@ static ssize_t show_dock_uid(struct device *dev,
                              struct device_attribute *attr, char *buf)
 {
         unsigned long lbuf;
-        acpi_status status = acpi_evaluate_integer(dock_station->handle, "_UID", 0, &lbuf);
+        acpi_status status = acpi_evaluate_integer(dock_station->handle, "_UID", NULL, &lbuf);
         if(ACPI_FAILURE(status)) {
             return 0;
         }