Staging: hv: vmbus: Cleanup vmbus_uevent() code

Now generate appropriate uevent based on the modalias string. As part of this,
cleanup the existing uevent code.

[gregkh - fixed code to handle driver_data portion of struct
hv_vmbus_device_id]

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>