fix compile error about missing evcnt definition.

picvar.h is now included very early because of uebayashi's change to sys/param.h.

sys/arch/arm/pic/picvar.h

@@ -1,4 +1,4 @@
-/*	$NetBSD: picvar.h,v 1.4 2008/12/30 05:43:14 matt Exp $	*/
+/*	$NetBSD: picvar.h,v 1.5 2010/11/15 09:25:58 bsh Exp $	*/
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -57,6 +57,8 @@ void	intr_disestablish(void *);
 
 #ifdef _INTR_PRIVATE
 
+#include <sys/evcnt.h>
+
 #ifndef PIC_MAXPICS
 #define PIC_MAXPICS	32
 #endif