perf stat: Choose the most disaggregate command line option

When multiple aggregation options are passed to perf stat the behavior
isn't clear. Consider "perf stat -A --per-socket .." and "perf stat
--per-socket -A ..", the first won't aggregate at all while the second
will do per-socket aggregation, even though the same options were
passed.

Rather than set an enum value, gather the options in a struct and
process them from most to least aggregate. This ensures the least
aggregate option always applies, so no aggregation if "-A" is passed.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240605063828.195700-2-irogers@google.com