tile: Make tile use the new is_idle_task() API

Change from direct comparison of ->pid with zero to is_idle_task().

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
index 25b7b90..c1eaaa1 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -54,7 +54,7 @@
 	if (unlikely(tsk->pid < 2)) {
 		panic("Signal %d (code %d) at %#lx sent to %s!",
 		      si_signo, si_code & 0xffff, address,
-		      tsk->pid ? "init" : "the idle task");
+		      is_idle_task(tsk) ? "the idle task" : "init");
 	}
 
 	info.si_signo = si_signo;
@@ -515,7 +515,7 @@
 
 	if (unlikely(tsk->pid < 2)) {
 		panic("Kernel page fault running %s!",
-		      tsk->pid ? "init" : "the idle task");
+		      is_idle_task(tsk) ? "the idle task" : "init");
 	}
 
 	/*