Build fix: Only <sys/cdefs.h> should be included before __FBSDID().

<sys/param.h> needs to be included after any "opt_foo.h" headers so it
sees the same set of defined macros as other headers.

sys/dev/filemon/filemon.c

@@ -25,11 +25,12 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/param.h>
+#include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include "opt_compat.h"
 
+#include <sys/param.h>
 #include <sys/file.h>
 #include <sys/systm.h>
 #include <sys/buf.h>