Staging: hv: Move probe_failed_work_item from vm_device

In preparation for consolidating all device related state into
struct hv_device, move probe_failed_work_item from vm_device to
hv_device.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Abhishek Kane <v-abkane@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>