perf tools: No need to include bitops.h in util.h

perf tools: No need to include bitops.h in util.h

When we switched to the kernel's roundup_pow_of_two we forgot to remove
this include from util.h, do it now.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 91529834d1de ("perf evlist: Use roundup_pow_of_two")
Link: http://lkml.kernel.org/n/tip-kfye5rxivib6155cltx0bw4h@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>