MFC 305962,305964-305967

MFC 305962,305964-305967

305962
    hyperv/hn: Don't allow NVS and NDIS version change upon reinitailization

    NVS and NDIS version change would break too much assumption and static
    configuration.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D7919

305964
    hyperv/hn: Save capabilities for later use.

    And don't allow capability changes during reinitialization, which
    breaks too much static configuration.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D7922

305965
    hyperv/hn: Don't allow MTU change, if it is not supported by the NVS.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D7923

305966
    hyperv/hn: Stringent RSS sysctl checks

    - Don't change RNDIS RSS configuration for RSS key sysctl, if the
      interface is not capable of RSS yet.
    - Don't change RSS indirect table (both cached one and RNDIS RSS
      configuration), if the interface is not capable of RSS yet.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D7924

305967
    hyperv/hn: Allow RSS capability flipping upon attach/reinit.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D7927

git-svn-id: svn://svn.freebsd.org/base/stable/10@307245 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f