linux-imx

MLK-16221-4 usb: cdns3: gadget: disable device mode when the gadget is stopped

After USB_CONF.DEVDS is set, the device mode will be disabled, and the
host will set the disconnection, this bit is just like DP pullup bit
at USB2.

And we add disable/enable device mode logic at .pullup function for
UDC core.

Signed-off-by: Peter Chen <peter.chen@nxp.com>
(cherry picked from commit 5847b6c6e62d9c8a11dd49305c1186c2abe9ccd9)