MFC 307989-307991,308010
307989
hyperv/hn: Move hn_softc to if_hnvar.h While I'm here, use consistent macro names. Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D8345
307990
hyperv/hn: Move send context to NVS domain. Since all sends are encapsulated in NVS messages. Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D8346
307991
hyperv/hn: NVS inclusion cleanup and forward declare functions. Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D8347
308010
hyperv/hn: Change header guardian; in preparation for the upcoming rename. Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D8352