perf cpumap: Remove needless includes from cpumap.h

The util/cpumap.h file doesn't use anything in refcount.h not in
debug.h, it needs just a forward reference to 'struct cpu_map_data',
that is defined in util/event.h and cpumap.h was getting indirectly via,
of all things, debug.h

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-mtjww98yptt4ppo6g2blavg5@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/svghelper.c

@@ -14,6 +14,7 @@
 #include <unistd.h>
 #include <string.h>
 #include <linux/bitmap.h>
+#include <linux/string.h>
 #include <linux/time64.h>
 #include <linux/zalloc.h>
 #include <perf/cpumap.h>