perf beauty ioctl cmd: The 'fd' arg is signed

perf beauty ioctl cmd: The 'fd' arg is signed

It is possible to pass a negative number as the fd and that has to be
handled, so stop using 'unsigned int fd' in the ioctl syscall 'cmd'
beautifier.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-b7qwa0l19dswa09h3s41akfu@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>