Azure: add support for Hyper-V sockets via VSOCK

[Marcelo Cerri]

SRU Justification:

Impact: linux-azure needs to support Hyper-V sockets to allow communication between the hypervisor and the virtual machines.

Fix: Sauce the following commits from https://github.com/dcui/linux.git :

c248b14174e1337c1461f9b13a573ad90a136e1c vmbus: vmbus_open(): reset onchannel_callback on error
008d8d8bc0c86473a8549a365bee9a479243e412 vmbus: add the matching tasklet_enable() in vmbus_close_internal()
4713066c11b2396eafd2873cbed7bdd72d1571eb vmbus: remove "goto error_clean_msglist" in vmbus_open()
1df677b35ff010d0def33f5420773015815cf843 vmbus: dynamically enqueue/dequeue a channel on vmbus_open/close
3476be340d2ff777609fca3e763da0292acbfc45 hv_sock: implements Hyper-V transport for Virtual Sockets (AF_VSOCK)
b5566b1b6e5cb19b381590587f841f950caabe4d VMCI: only try to load on VMware hypervisor
6f1aa69011356ff95ed6c57400095e5f2d9eb900 hv_sock: add the support of auto-loading
2fac74605d2db862caaaf4890239b57095fba832 tools: hv_sock: 2 simple test cases.
2e307800c6a01cd789afe34eccbcabf384959b3f vmbus: introduce in-place packet iterator
83c8635b893bbc0b5b329c632cea0382d5479763 hvsock: fix a race in hvs_stream_dequeue()
29e6c6204845176c78c7840377a72389d188563c hvsock: fix vsock_dequeue/enqueue_accept race
6172aa1bbfb66a9e0b0da0f162f0e91c129e3c94 Drivers: hv: vmbus: Fix rescind handling
24ff598cdf98290b25805219eff78336bc08e5ab vmbus: fix hv_percpu_channel_deq/enq race
9a00fd7c4ad9c5d1da39c3c44328145fe063ceed vmbus: add vmbus onoffer/onoffer_rescind sync.

Testcase: ?