perf evsel: Enable type checking for perf_evsel_config_term types

perf evsel: Enable type checking for perf_evsel_config_term types

Use a typed enum for the perf_evsel_config_term type enum.  This allows
gcc to do much stronger type checks, and also check for missing case
statements.

I removed the unused _MAX member from the number.

It found one missing case. I'm not sure it's a real problem, so I just
turned it into a BUG_ON for now.

Signed-off-by: Andi Kleen <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ Renamed the enum name to term_type as per jolsa's request ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>