On Sandy Bridge and later, to count branch-related events you
have to or together a mask indicating the type of branch
instruction to count (e.g. direct jump, branch, etc) and a bits
indicating whether to count taken and not-taken branches. The
current counter definitions where defining this bits individually,
so the counters never worked and always just counted 0.
Fix the counter definitions to instead contain the proper
combination of masks. Also update the man pages to reflect the
new counters.