perf report: Don't show unresolved DSOs and symbols when -S/-d is used

We're interested in just those symbols/DSOs, so filter out the
unresolved ones.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20090812211957.GE3495@ghostprotocols.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>