perf map: Remove needless struct forward declarations

At some point we may have needed that, not anymore.

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-hnao13231bsl7xml5wn8h4iu@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/map.h

@@ -12,11 +12,8 @@
 #include <linux/types.h>
 
 struct dso;
-struct ip_callchain;
-struct ref_reloc_sym;
 struct map_groups;
 struct machine;
-struct evsel;
 
 struct map {
 	union {