usb: cdnsp: Fix incorrect supported maximum speed

Driver had hardcoded in initialization maximum supported speed
to USB_SPEED_SUPER_PLUS but it should consider the speed
returned from usb_get_maximum_speed function.

Fixes: 3d82904 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
Link: https://lore.kernel.org/r/20210625102502.26336-1-pawell@gli-login.cadence.com
Signed-off-by: Peter Chen <peter.chen@kernel.org>

Author: pawellcdns

drivers/usb/cdns3/cdnsp-gadget.c

@@ -1882,7 +1882,7 @@ static int __cdnsp_gadget_init(struct cdns *cdns)
 	pdev->gadget.name = "cdnsp-gadget";
 	pdev->gadget.speed = USB_SPEED_UNKNOWN;
 	pdev->gadget.sg_supported = 1;
-	pdev->gadget.max_speed = USB_SPEED_SUPER_PLUS;
+	pdev->gadget.max_speed = max_speed;
 	pdev->gadget.lpm_capable = 1;
 
 	pdev->setup_buf = kzalloc(CDNSP_EP0_SETUP_SIZE, GFP_KERNEL);