perf ui browser: Introduce ui_browser__show_title

Needed because we were only showing the title in ui_browser__show,
not in ui_browser__run, and in the run loop we may be calling other
browsers that would then change the title, when we go back to the
previous browser, we need to redraw the title.

We could have done this as the Newt help line, with pop, etc, but I
don't think its worth, doing it explicitely, when needed (some browsers
may not use the title area at all) seems enough/more flexible.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>