fuse: mark UtimeToTimespec as deprecated.

Change-Id: Ib094e7e55f922780408223626d88388d2cc5f8b6

fuse/misc.go

@@ -73,6 +73,8 @@ func CurrentOwner() *Owner {
 // UtimeToTimespec converts a "Time" pointer as passed to Utimens to a
 // "Timespec" that can be passed to the utimensat syscall.
 // A nil pointer is converted to the special UTIME_OMIT value.
+//
+// Deprecated: use unix.TimeToTimespec from the x/sys/unix package instead.
 func UtimeToTimespec(t *time.Time) (ts syscall.Timespec) {
 	if t == nil {
 		ts.Nsec = _UTIME_OMIT