touch: fix warnings from useless_conversion lint (#11203)

Author: cakebaker

src/uu/touch/src/touch.rs

@@ -622,14 +622,21 @@ fn try_futimens_via_write_fd(path: &Path, atime: FileTime, mtime: FileTime) -> s
     let mtime_sec = mtime.unix_seconds();
     let mtime_nsec = i64::from(mtime.nanoseconds());
 
+    #[cfg(target_pointer_width = "32")]
     let atime_spec = TimeSpec::new(
         atime_sec.try_into().unwrap(),
         atime_nsec.try_into().unwrap(),
     );
+    #[cfg(target_pointer_width = "64")]
+    let atime_spec = TimeSpec::new(atime_sec, atime_nsec);
+
+    #[cfg(target_pointer_width = "32")]
     let mtime_spec = TimeSpec::new(
         mtime_sec.try_into().unwrap(),
         mtime_nsec.try_into().unwrap(),
     );
+    #[cfg(target_pointer_width = "64")]
+    let mtime_spec = TimeSpec::new(mtime_sec, mtime_nsec);
 
     futimens(&file, &atime_spec, &mtime_spec).map_err(Error::from)
 }