Added missing include of "opt_cpu.h". I missed it because PERFMON

features are used without testing for i586 features that they depend
on.  Configuring option PERFMON without configuring a suitable cpu
still doesn't fail right.

sys/i386/i386/perfmon.c

@@ -26,9 +26,11 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: perfmon.c,v 1.6 1996/06/12 05:02:51 gpalmer Exp $
+ *	$Id: perfmon.c,v 1.7 1996/08/02 21:15:48 bde Exp $
  */
 
+#include "opt_cpu.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/fcntl.h>