gspca: Fix bulk mode cameras no longer working (regression fix)

The new iso bandwidth calculation code accidentally has broken support
for bulk mode cameras. This has broken the following drivers:
finepix, jeilinj, ovfx2, ov534, ov534_9, se401, sq905, sq905c, sq930x,
stv0680, vicam.

Thix patch fixes this. Fix tested with: se401, sq905, sq905c, stv0680 & vicam
cams.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/media/video/gspca/gspca.c

@@ -838,13 +838,13 @@ static int gspca_init_transfer(struct gspca_dev *gspca_dev)
 	gspca_dev->usb_err = 0;
 
 	/* do the specific subdriver stuff before endpoint selection */
-	gspca_dev->alt = 0;
+	intf = usb_ifnum_to_if(gspca_dev->dev, gspca_dev->iface);
+	gspca_dev->alt = gspca_dev->cam.bulk ? intf->num_altsetting : 0;
 	if (gspca_dev->sd_desc->isoc_init) {
 		ret = gspca_dev->sd_desc->isoc_init(gspca_dev);
 		if (ret < 0)
 			goto unlock;
 	}
-	intf = usb_ifnum_to_if(gspca_dev->dev, gspca_dev->iface);
 	xfer = gspca_dev->cam.bulk ? USB_ENDPOINT_XFER_BULK
 				   : USB_ENDPOINT_XFER_ISOC;