perf hists browser: Split popup menu actions - part 2

Currently perf_evsel__hists_browse() function spins on a huge loop and
handles many key actions.  Since it's hard to read and modify, let's
split it out into small helper functions.

The add_XXX_opt() functions are to register popup menu item on the
selected entry.  When it adds an item, it also saves related data into
struct popup_action and returns 1 so that it can increase the number of
items (nr_options).

With this change, we can simplify the code just to call selected
callback function without considering various conditions.  A callback
function named do_XXX is called with saved data when the item is
selected by user.

No functional change intended.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1429687101-4360-9-git-send-email-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>