Staging: hv: util: Perform some service specific init/deinit in probe/remove

In preparation for modifying the util driver to fully conform to the
Linux Driver Model, perform some service specific init and de-init
operations in util_probe()/util_remove()  as opposed to in
init_hyperv_utils()/exit_hyperv_utils() as is currently done.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>