Add $FreeBSD$ to ancient sources that it's missing from.

Sponsored by: Netflix

lib/libstand/bootparam.h

@@ -1,4 +1,5 @@
 /*	$NetBSD: bootparam.h,v 1.3 1998/01/05 19:19:41 perry Exp $	*/
+/*	$FreeBSD$ */
 
 int bp_whoami(int sock);
 int bp_getfile(int sock, char *key, struct in_addr *addrp, char *path);

lib/libstand/tftp.h

@@ -30,6 +30,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
+ * $FreeBSD$
  */