perf tools: Remove some duplicated includes

There exists some duplicated includes in tools/perf, remove them.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: xuefeng li <lixuefeng@loongson.cn>
Link: http://lore.kernel.org/lkml/1591071304-19338-2-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/config.c

@@ -21,7 +21,6 @@
 #include "build-id.h"
 #include "debug.h"
 #include "config.h"
-#include "debug.h"
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <stdlib.h>