xen/events: Remove unused bind_evtchn_to_irq_lateeoi()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20201210194044.972064156@linutronix.de