Remove unneeded D_NEEDMINOR from cpuctl(4).

The D_NEEDMINOR flag was introduced for drivers that do not actually
depend on storing a device unit/minor number, but require the ability to
address the cdevs by this number, which is used by clone_create().

The cpuctl(4) driver sets D_NEEDMINOR, even though it doesn't use the
clone_create() API. Remove the flag, because maybe we want to get rid of
it somewhere in the far future.

sys/dev/cpuctl/cpuctl.c

@@ -80,7 +80,6 @@ static MALLOC_DEFINE(M_CPUCTL, "cpuctl", "CPUCTL buffer");
 
 static struct cdevsw cpuctl_cdevsw = {
         .d_version =    D_VERSION,
-        .d_flags =      D_NEEDMINOR,
         .d_open =       cpuctl_open,
         .d_ioctl =      cpuctl_ioctl,
         .d_name =       "cpuctl",