MFC 306426

MFC 306426

    hyperv/storvsc: Fix the blkvsc disk attachment issues.

    - The original 'disengage' ATA controller model does not work properly
      for all possible disk configurations.  Use the newly added ATA disk
      veto eventhandler to fit into all possible disk configuration.
    - If the 'invalid LUN' happens on blkvsc controllers, return
      CAM_DEV_NOT_THERE so that CAM will not destroy attached disks under
      the blkvsc controllers.

    Submitted by:   Hongjiang Zhang <honzhan microsoft com>
    Discussed with: mav
    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D7693

git-svn-id: svn://svn.freebsd.org/base/stable/10@307254 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f