Staging: hv: Fix a bug in vmbus_match()

The recent checkin that add a private pointer to hv_vmbus_device_id
introduced this bug in vmbus_match; fix it.

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>