perf top: Cleanup condition in perf_top__record_precise_ip()

perf top: Cleanup condition in perf_top__record_precise_ip()

The 'he' cannot be NULL since it's caller hist_iter__top_callback() is
called only if iter->he is not NULL (see hist_entry_iter__add).  So
setting 'sym' before the condition to simplify the code.

Also make it clearer that the top->symbol_filter_entry check is only
meaningful on stdio mode (i.e. when use_browser is 0).

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1449802616-16170-4-git-send-email-namhyung@kernel.org
[ Complete the simplification replacing one more he->ms.sym with sym ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>