perf top: Allow passing a kallsyms file

perf top: Allow passing a kallsyms file

This basically replicates what was done for 'perf report' in:

   c586231aba46 ("perf report: Allow user to specify path to kallsyms file")

This should help with resolving eBPF symbols, that are in kallsyms but,
of course, not in vmlinux.

Reported-by: Ivan Babrou <ibobrik@gmail.com>
Tested-by: Ivan Babrou <ibobrik@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-x52mx1ybq8128rtg9hjrj5qk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>