usb: gadget: add 'quirk_altset_not_supp' to usb_gadget

Due to some UDC controllers may not support altsettings, usb gadget layer
needs to provide a generic way to inform gadget functions about non-standard
hardware limitations.

This patch adds 'quirk_altset_not_supp' field to struct usb_gadget and helper
function gadget_is_altset_supported(). It also sets 'quirk_altset_not_supp'
to 1 in pxa25x_udc and pxa27x_udc drivers, which have such limitation.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/udc/pxa27x_udc.c

@@ -1710,6 +1710,7 @@ static void udc_init_data(struct pxa_udc *dev)
 	INIT_LIST_HEAD(&dev->gadget.ep_list);
 	INIT_LIST_HEAD(&dev->gadget.ep0->ep_list);
 	dev->udc_usb_ep[0].pxa_ep = &dev->pxa_ep[0];
+	dev->gadget.quirk_altset_not_supp = 1;
 	ep0_idle(dev);
 
 	/* PXA endpoints init */