6149 use NULL capable segop as a shorthand for no-capabilities

*** 497,513 ****
          memid->val[0] = (uintptr_t)VTOCVP(data->vp);
          memid->val[1] = (uintptr_t)seg_page(seg, addr);
          return (0);
  }
  
- /*ARGSUSED*/
- static int
- segmf_capable(struct seg *seg, segcapability_t capability)
- {
-         return (0);
- }
- 
  /*
   * Add a set of contiguous foreign MFNs to the segment. soft-locking them.  The
   * pre-faulting is necessary due to live migration; in particular we must
   * return an error in response to IOCTL_PRIVCMD_MMAPBATCH rather than faulting
   * later on a bad MFN.  Whilst this isn't necessary for the other MMAP
--- 497,506 ----
*** 769,775 ****
          .advise         = segmf_advise,
          .dump           = segmf_dump,
          .pagelock       = segmf_pagelock,
          .setpagesize    = segmf_setpagesize,
          .getmemid       = segmf_getmemid,
-         .capable        = segmf_capable,
  };
--- 762,767 ----