perf ui: Move objdump_line specific stuff out of ui_browser

By adding a ui_browser->refresh_entries() pure virtual member.

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
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>