perf map: Ditch leftover map__reloc_vmlinux() prototype

In 39b12f78 ("perf tools: Make it possible to read object code from vmlinux")
the actual function was removed, but we forgot to remove the prototype,
fix it.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-35yy50cgpcx8cjorluwd5j53@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>