perf symbols: Change the kernel DSO name if it comes from kallsyms

So that the user have a clearer indication about the source of
the symbols, as we only state buildid mismatches in verbose
mode, because 'perf top' would overwrite such warning anyway.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1258757489-5978-6-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>