perf stat: Fix the ratio comments of miss-events

'perf stat' displays miss ratio of L1-dcache, L1-icache, dTLB cache,
iTLB cache and LL-cache. Take L1-dcache for example, miss ratio is
caculated as "L1-dcache-load-misses/L1-dcache-loads". So "of all
L1-dcache hits" is unsuitable to describe it, and "of all L1-dcache
accesses" seems better.

The comments of L1-icache, dTLB cache, iTLB cache and LL-cache are
fixed in the same way.

Signed-off-by: Qi Liu <liuqi115@huawei.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: linuxarm@huawei.com
Link: http://lore.kernel.org/lkml/1600253331-10535-1-git-send-email-liuqi115@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>