usb: dwc3: gadget: change detemination method of connect status

usb: dwc3: gadget: change detemination method of connect status

In current code, the connect status will be set to connected state when
reset interrupt occur and change to disconnected state in disconnect
interrupt.

But the usb charger may bring about reset signal in accident if we
connect and disconnect quickly. In this case, the dwc3 controller will
change link state and set to connect status, yet not change to
disconnected state when disconnect. So the dwc3 controller suspend
fail and result in a mistake when quick reconnect.

This patch set connect status to connected state when transfer complete
to make sure that usb is connect to PC exactly.

Change-Id: I8e5894d2e08b88bb5434222100d8f5c91c9f1a9d
Signed-off-by: Meng Dongyang <daniel.meng@rock-chips.com>