11839 ipmi_close can panic trying to free invalid dev_t
Reviewed by: Andy Stormont <astormont@racktopsystems.com>
Reviewed by: Garrett D'Amore <garrett@damore.org>

*** 160,170 ****
  
          /* exclusive opens are not supported */
          if (flag & FEXCL)
                  return (ENOTSUP);
  
!         if ((minor = (minor_t)id_alloc_nosleep(minor_ids)) == 0)
                  return (ENODEV);
  
          /* Initialize the per file descriptor data. */
          dev = kmem_zalloc(sizeof (ipmi_device_t), KM_SLEEP);
  
--- 160,170 ----
  
          /* exclusive opens are not supported */
          if (flag & FEXCL)
                  return (ENOTSUP);
  
!         if ((minor = (minor_t)id_alloc_nosleep(minor_ids)) == (minor_t)(-1))
                  return (ENODEV);
  
          /* Initialize the per file descriptor data. */
          dev = kmem_zalloc(sizeof (ipmi_device_t), KM_SLEEP);