Remove unnecessary unsafe from time refcount rules (#495)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Nuno Lopes <nuno.lopes@tecnico.ulisboa.pt>

Author: Copilot

rules/time/tgt_refcount.rs

@@ -164,15 +164,15 @@ fn f8(a0: Ptr<Timeval>, a1: AnyPtr) -> i32 {
     }
 }
 
-unsafe fn f9() -> nix::time::ClockId {
+fn f9() -> nix::time::ClockId {
     nix::time::ClockId::CLOCK_REALTIME
 }
 
-unsafe fn f10() -> nix::time::ClockId {
+fn f10() -> nix::time::ClockId {
     nix::time::ClockId::CLOCK_MONOTONIC
 }
 
 #[cfg(target_os = "linux")]
-unsafe fn f11() -> nix::time::ClockId {
+fn f11() -> nix::time::ClockId {
     nix::time::ClockId::CLOCK_MONOTONIC_RAW
 }