bpftool: Dump the kernel symbol's module name

If the kernel symbol is in a module, we will dump the module name as
well. The square brackets around the module name are trimmed.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230709025630.3735-3-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>