perf test vmlinux: Remove dead symbol_filter_t code

perf test vmlinux: Remove dead symbol_filter_t code

We don't need to initialize that area as we're not using it afterwards,
leftover, ditch it.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-jb2un8buy4rqawz73mcdm1sn@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>