perf symbols: Look at .dynsym again if .symtab not found

The original intent of the code was to repeat the search with
want_symtab = 0. But as the code stands now, we never hit the "default"
case of the switch statement. Which means we never repeat the search.

Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reported-by: Arun Sharma <asharma@fb.com>
Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Dave Martin <dave.martin@linaro.org>
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>