hv_utils: update name in struct hv_driver util_drv

The correct module name is hv_utils. This patch corrects
the name in struct hv_driver util_drv.

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