Drivers: hv: vmbus: Implement a clockevent device

Implement a clockevent device based on the timer support available on
Hyper-V.
In this version of the patch I have addressed Jason's review comments.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc arch/x86/include/uapi/asm/hyperv.h
Simple merge

diff --cc drivers/hv/hv.c
Simple merge

diff --cc drivers/hv/hyperv_vmbus.h
Simple merge

diff --cc drivers/hv/vmbus_drv.c
Simple merge