MFC 308117-308120

MFC 308117-308120

308117
    hyperv/hn: Rework temporary channel packet buffer expanding.

    And use large default temporary channel packer buffer; we really
    don't want it to be expanded at run time.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D8367

308118
    hyperv/hn: Cleanup RXBUF ack processing.

    - Increase the # of retries.
    - Add comment.
    - Log error, if RXBUF ack fails.
    - Add stat for RXBUF ack failures.

    RXBUF ack really should _not_ fail...

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D8368

308119
    hyperv/hn: Reset do_lro, if the hash types are not TCP related.

    Mainly because the host side only set TCPCS and IPCS even for
    UDP datagrams.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D8369

308120
    hyperv/hn: Don't start shared TX taskq, if the hypervisor is not Hyper-V.

    - Move the SYSINIT to DRIVER/SECOND, i.e. after the vm_guest becomes
      determistic.
    - Minor style changes.

    Sponsored by:   Microsoft
    Differential Revision:  https://reviews.freebsd.org/D8370