perf symbols: No need to special case MAP__FUNCTION in fixup

perf symbols: No need to special case MAP__FUNCTION in fixup

In 39b12f781271 ("perf tools: Make it possible to read object code from
vmlinux") we special case MAP__FUNCTION maps inconsistently, the first
test tests the map type while the following tests added by this patch
don't do that, be consistent and elliminate this special case.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
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-khmi5jccpcwqa9nybefluzqp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>