drivers:hv: Export the API to invoke a hypercall on Hyper-V
This patch exposes the function that hv_vmbus.ko uses to make hypercalls. This
is necessary for retargeting an interrupt when it is given a new affinity.
Since we are exporting this API, rename the API as it will be visible outside
the hv.c file.
Signed-off-by: Jake Oshins <jakeo@microsoft.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>