perf units: Move parse_tag_value() to units.[ch]

Its basically to do units handling, so move to a more appropriately
named object.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-90ob9vfepui24l8l2makhd9u@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
4 files changed