Export perf_event_update_userpage() so that PMU driver using them,
can be built as modules.
Acked-by: NPeter Zilstra <peterz@infradead.org>
Signed-off-by: NSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>