upgt.4: bump removal to 16.0

It was not actually removed prior to FreeBSD 15.0.

Sponsored by:	The FreeBSD Foundation

share/man/man4/upgt.4

@@ -48,7 +48,7 @@
 .\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd February 18, 2025
+.Dd October 24, 2025
 .Dt UPGT 4
 .Os
 .Sh NAME
@@ -78,7 +78,7 @@ if_upgt_load="YES"
 The
 .Nm
 driver is slated to be removed in
-.Fx 15.0 .
+.Fx 16.0 .
 .Sh DESCRIPTION
 The
 .Nm