FROMGIT: usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend

In current scenario if Plug-out and Plug-In performed continuously
there could be a chance while checking for dwc->gadget_driver in
dwc3_gadget_suspend, a NULL pointer dereference may occur.

Call Stack:

	CPU1:                           CPU2:
	gadget_unbind_driver            dwc3_suspend_common
	dwc3_gadget_stop                dwc3_gadget_suspend
                                        dwc3_disconnect_gadget

CPU1 basically clears the variable and CPU2 checks the variable.
Consider CPU1 is running and right before gadget_driver is cleared
and in parallel CPU2 executes dwc3_gadget_suspend where it finds
dwc->gadget_driver which is not NULL and resumes execution and then
CPU1 completes execution. CPU2 executes dwc3_disconnect_gadget where
it checks dwc->gadget_driver is already NULL because of which the
NULL pointer deference occur.

Cc: <stable@vger.kernel.org>
Fixes: 9772b47a ("usb: dwc3: gadget: Fix suspend/resume during device mode")
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Uttkarsh Aggarwal <quic_uaggarwa@quicinc.com>

(cherry picked from commit 61a34885 )

Bug: 322899161
Link: https://lore.kernel.org/all/20240119094825.26530-1-quic_uaggarwa@quicinc.com/


Change-Id: I2f1663f19ebdd6c6b5b1874a66c81fd3f75b0e9a
Signed-off-by: Rajashekar kuruva <quic_kuruva@quicinc.com>