perf stat: Remove duplicated include in builtin-stat.c

perf stat: Remove duplicated include in builtin-stat.c

util/topdown.h is included twice in builtin-stat.c,
remove one of them.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Tested-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=1818
Link: https://lore.kernel.org/r/20220804005213.71990-1-yang.lee@linux.alibaba.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>