Input: aiptek - use descriptors of current altsetting

Make sure to always use the descriptors of the current alternate setting
to avoid future issues when accessing fields that may differ between
settings.
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Vladis Dronov <vdronov@redhat.com>
Link: https://lore.kernel.org/r/20191210113737.4016-4-johan@kernel.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/tablet/aiptek.c

@@ -1713,7 +1713,7 @@ aiptek_probe(struct usb_interface *intf, const struct usb_device_id *id)
 
 	aiptek->inputdev = inputdev;
 	aiptek->intf = intf;
-	aiptek->ifnum = intf->altsetting[0].desc.bInterfaceNumber;
+	aiptek->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
 	aiptek->inDelay = 0;
 	aiptek->endDelay = 0;
 	aiptek->previousJitterable = 0;