[media] gspca - main: Fix a regression with the PS3 Eye webcam

When audio is present, some alternate settings were skipped.
This prevented some webcams to work, especially when bulk transfer was used.
This patch permits to use the last or only alternate setting.
Reported-by: NAntonio Ospite <ospite@studenti.unina.it>
Tested-by: NAntonio Ospite <ospite@studenti.unina.it>
Signed-off-by: NJean-François Moine <moinejf@free.fr>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/gspca/gspca.c

@@ -652,7 +652,7 @@ static struct usb_host_endpoint *get_ep(struct gspca_dev *gspca_dev)
 				   : USB_ENDPOINT_XFER_ISOC;
 	i = gspca_dev->alt;			/* previous alt setting */
 	if (gspca_dev->cam.reverse_alts) {
-		if (gspca_dev->audio)
+		if (gspca_dev->audio && i < gspca_dev->nbalt - 2)
 			i++;
 		while (++i < gspca_dev->nbalt) {
 			ep = alt_xfer(&intf->altsetting[i], xfer);
@@ -660,7 +660,7 @@ static struct usb_host_endpoint *get_ep(struct gspca_dev *gspca_dev)
 				break;
 		}
 	} else {
-		if (gspca_dev->audio)
+		if (gspca_dev->audio && i > 1)
 			i--;
 		while (--i >= 0) {
 			ep = alt_xfer(&intf->altsetting[i], xfer);