perf kvm stat: Replace kvm-stat.h includes with forward declarations

To reduce the include header dependency tree and speed up perf builds.

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-dngwaxuhfnhksawgdpo6e74n@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/arch/s390/util/kvm-stat.c

@@ -11,6 +11,7 @@
 
 #include <errno.h>
 #include "../../util/kvm-stat.h"
+#include "../../util/evsel.h"
 #include <asm/sie.h>
 
 define_exit_reasons_table(sie_exit_reasons, sie_intercept_code);