Drivers: hv: vmbus: move init_vp_index() call to vmbus_process_offer()

Drivers: hv: vmbus: move init_vp_index() call to vmbus_process_offer()

We need to call init_vp_index() after we added the channel to the appropriate
list (global or subchannel) to be able to use this information when assigning
the channel to the particular vcpu. To do so we need to move a couple of
functions around. The only real change is the init_vp_index() call. This is a
small refactoring without a functional change.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit f38e7dd72337d83cced910cfbf6016475ef85bf7)

Orabug: 21886720
Signed-off-by: Jason Luo <zhangqing.luo@oracle.com>