libtraceevent: Fixed description of tep_add_plugin_path() API

libtraceevent: Fixed description of tep_add_plugin_path() API

Changed the description of tep_add_plugin_path() API to reflect the
logic of the function. The suffix of plugin files is not hardcoded
to ".so", it depends on the custom plugin loader callback.

Link: https://lore.kernel.org/CAM9d7cgMgqFDvKhs6xwdBSMsaG=3ZG0RtxwgQDCTLGkML1MY4Q@mail.gmail.com
Link: https://lore.kernel.org/linux-trace-devel/20200714103027.2477584-8-tz.stoyanov@gmail.com
Link: https://lore.kernel.org/linux-trace-devel/20200716092014.2613403-8-tz.stoyanov@gmail.com
Suggested-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: linux-trace-devel@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200722011755.581468845@goodmis.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>