tick/nohz: Remove unused tick_nohz_idle_stop_tick_protected()

All the caller has been removed since commit 336f560a

 ("x86/xen: don't
let xen_pv_play_dead() return")

Signed-off-by: Xueshi Hu <xueshi.hu@smartx.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230912104406.312185-5-frederic@kernel.org