percpu_counters: use for_each_online_cpu()
percpu_counters: use for_each_online_cpu()

Now that we have implemented hotunplug-time counter spilling,
percpu_counter_sum() only needs to look at online CPUs.

Cc: Gautham R Shenoy <c13571dbffa0eb89c7f8eebdce482897b0f5a685@in.ibm.com>
Cc: Oleg Nesterov <20b70f0af00562e63758b9ee42012ecc96c58590@tv-sign.ru>
Cc: Peter Zijlstra <645ca7d3a8d3d4f60557176cd361ea8351edc32b@chello.nl>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs