x86: small sparse fix in process_32.c

arch/x86/kernel/process_32.c:254:43: warning: Using plain integer as NULL pointer

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 968371a..dabdbef 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -251,7 +251,7 @@
 		 * because it has nothing to do.
 		 * Give all the remaining CPUS a kick.
 		 */
-		smp_call_function_mask(map, do_nothing, 0, 0);
+		smp_call_function_mask(map, do_nothing, NULL, 0);
 	} while (!cpus_empty(map));
 
 	set_cpus_allowed(current, tmp);