This patch add support for page fault count, major fault count
and minorfault count. Without this patch page faults are not
sampled for perf event.

Performance counter stats for '/usr/lib/perf-test/callchain_test':
	0      page-faults               #    0.000 K/sec
Signed-off-by: Mao Han <han_mao@c-sky.com>
Signed-off-by: Guo Ren <ren_guo@c-sky.com>