sparc64: Prepare perf event layer for handling multiple PCR registers.

Make the per-cpu pcr save area an array instead of one u64.

Describe how many PCR and PIC registers the chip has in the sparc_pmu
descriptor.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc arch/sparc/kernel/perf_event.c
Simple merge