MFC 306484,306485
306484
hyperv/vmbus: Add missing vmbus_if.c to module build. Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D8067
306485
hyperv/hn: Add stubs for OFFLOAD_CURRENT_CONFIG and NETWORK_CHANGE status Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D8068