Perf: Restore correct CPU's PMU counters after power collpase

Since the L1CC PMU's are per CPU, the variable to detect if a CPU
came out of powercollapse also needs to be a per CPU variable. This
ensures that we reset and restore the correct CPU's PMU counters.

Change-Id: I02273df2eff9f6d88d68f46a7752c107b290a8ef
Signed-off-by: Ashwin Chaugule <ashwinc@codeaurora.org>