usb: cdnsp: Fix lack of spin_lock_irqsave/spin_lock_restore

Patch puts content of cdnsp_gadget_pullup function inside
spin_lock_irqsave and spin_lock_restore section.
This construction is required here to keep the data consistency,
otherwise some data can be changed e.g. from interrupt context.

Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Reported-by: Ken (Jian) He <[e-mail]>
cc: <[e-mail]>
Signed-off-by: Pawel Laszczak <[e-mail]>
--

Changelog:
v2:
- added disable_irq/enable_irq as sugester by Peter Chen

drivers/usb/cdns3/cdnsp-gadget.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

Reviewed-by: Peter Chen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/cdns3/cdnsp-gadget.c

···
 {
 	struct cdnsp_device *pdev = gadget_to_cdnsp(gadget);
 	struct cdns *cdns = dev_get_drvdata(pdev->dev);
+	unsigned long flags;
 
 	trace_cdnsp_pullup(is_on);
+
+	/*
+	 * Disable events handling while controller is being
+	 * enabled/disabled.
+	 */
+	disable_irq(cdns->dev_irq);
+	spin_lock_irqsave(&pdev->lock, flags);
 
 	if (!is_on) {
 		cdnsp_reset_device(pdev);
···
 	} else {
 		cdns_set_vbus(cdns);
 	}
+
+	spin_unlock_irqrestore(&pdev->lock, flags);
+	enable_irq(cdns->dev_irq);
+
 	return 0;
 }