tick/broadcast: Make tick_broadcast_setup_oneshot() static

This function isn't used outside of tick-broadcast.c, so let's
mark it static.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Link: http://lkml.kernel.org/r/20170608063603.13276-1-sboyd@codeaurora.org


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>