sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

cpukit/include/sys/_ffcounter.h

@@ -36,8 +36,6 @@
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
- *
- * $FreeBSD r277406 2015-01-20T03:54:30Z$
  */
 
 #ifndef _SYS__FFCOUNTER_H_

cpukit/include/sys/timeffc.h

@@ -36,8 +36,6 @@
  * LIABILITY, OR TORT (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: head/sys/sys/timeffc.h 228856 2011-12-24 01:32:01Z lstewart $
  */
 
 #ifndef _SYS_TIMEFF_H_

cpukit/include/sys/timepps.h

@@ -21,8 +21,6 @@
  * Portions of this software were developed by Julien Ridoux at the University
  * of Melbourne under sponsorship from the FreeBSD Foundation.
  *
- * $FreeBSD: head/sys/sys/timepps.h 282424 2015-05-04 17:59:39Z ian $
- *
  * The is a FreeBSD version of the RFC 2783 API for Pulse Per Second 
  * timing interfaces.  
  */

cpukit/include/sys/timetc.h

@@ -14,8 +14,6 @@
  * can do whatever you want with this stuff. If we meet some day, and you think
  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
  * ----------------------------------------------------------------------------
- *
- * $FreeBSD: head/sys/sys/timetc.h 304285 2016-08-17 09:52:09Z kib $
  */
 
 #ifndef _SYS_TIMETC_H_

cpukit/include/sys/timex.h

@@ -27,8 +27,6 @@
  *								       *
  ***********************************************************************
  *
- * $FreeBSD: head/sys/sys/timex.h 298981 2016-05-03 15:14:17Z pfg $
- *
  * This header file defines the Network Time Protocol (NTP) interfaces
  * for user and daemon application programs.
  *