tests: fix error for uptime on OpenBSD

Signed-off-by: Laurent Cheylus <foxy@free.fr>

Author: lcheylus

tests/by-util/test_uptime.rs

@@ -6,7 +6,6 @@
 // spell-checker:ignore bincode serde utmp runlevel testusr testx
 #![allow(clippy::cast_possible_wrap, clippy::unreadable_literal)]
 
-#[cfg(not(target_os = "openbsd"))]
 use uutests::at_and_ucmd;
 use uutests::util::TestScenario;
 use uutests::{new_ucmd, util_name};