perf hists browser: Honour the help line provided by builtin-{top,report}.c

perf hists browser: Honour the help line provided by builtin-{top,report}.c

The hists_browser was replacing whatever helpline provided by 'top' or
'report' with a static "Press '?' for help on key bindings", fix it.

Now the message passed by top appears at the bottom of the screen:

"For a higher level overview, try: perf top --sort comm,dso"

As well the message that will be added when the user presses 'f' to
disable the events, something along the lines of "press f again to
re-enable...".

Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Don Zickus <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>