perf callchain: Make get_srcline fall back to sym+offset

When the source line is not found fall back to sym + offset.  This is
generally much more useful than a raw address.

For this we need to pass in the symbol from the caller.

For some callers it's awkward to compute, so we stay at the old
behaviour.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1415844328-4884-10-git-send-email-andi@firstfloor.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>