Move calling delay_autosuspend() in rtl8152_runtime_suspend(). Calling
delay_autosuspend() as late as possible.

The original flows are
   1. check if the driver/device is busy now.
   2. set wake events.
   3. enter runtime suspend.

If the wake event occurs between (1) and (2), the device may miss it. Besides,
to avoid the runtime resume occurs after runtime suspend immediately, move the
checking to the end of rtl8152_runtime_suspend().

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>