Fill the 'card' member of v4l2_capability struct with the usb product

name coming from usbd_devinfo_vp() instead of the dummy "Generic USB
video class device" string, makes it easier to differentiate multiple
webcams in firefox's webrtc permission dialog.

ok/help mpi@

sys/dev/usb/usb_subr.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: usb_subr.c,v 1.134 2017/04/08 02:57:25 deraadt Exp $ */
+/*	$OpenBSD: usb_subr.c,v 1.135 2018/04/24 17:22:33 landry Exp $ */
 /*	$NetBSD: usb_subr.c,v 1.103 2003/01/10 11:19:13 augustss Exp $	*/
 /*	$FreeBSD: src/sys/dev/usb/usb_subr.c,v 1.18 1999/11/17 22:33:47 n_hibma Exp $	*/
 
@@ -61,8 +61,6 @@ extern int usbdebug;
 
 usbd_status	usbd_set_config(struct usbd_device *, int);
 void		usbd_devinfo(struct usbd_device *, int, char *, size_t);
-void		usbd_devinfo_vp(struct usbd_device *, char *, size_t,
-		    char *, size_t, int);
 char		*usbd_get_device_string(struct usbd_device *, uByte);
 char		*usbd_get_string(struct usbd_device *, int, char *, size_t);
 int		usbd_getnewaddr(struct usbd_bus *);

sys/dev/usb/usbdivar.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: usbdivar.h,v 1.73 2018/02/03 13:37:37 mpi Exp $ */
+/*	$OpenBSD: usbdivar.h,v 1.74 2018/04/24 17:22:33 landry Exp $ */
 /*	$NetBSD: usbdivar.h,v 1.70 2002/07/11 21:14:36 augustss Exp $	*/
 /*	$FreeBSD: src/sys/dev/usb/usbdivar.h,v 1.11 1999/11/17 22:33:51 n_hibma Exp $	*/
 
@@ -257,6 +257,8 @@ usbd_status	usbd_fill_iface_data(struct usbd_device *, int, int);
 usbd_status	usb_insert_transfer(struct usbd_xfer *);
 void		usb_transfer_complete(struct usbd_xfer *);
 int		usbd_detach(struct usbd_device *, struct device *);
+void		usbd_devinfo_vp(struct usbd_device *, char *, size_t,
+		    char *, size_t, int);
 
 /* Routines from usb.c */
 void		usb_needs_explore(struct usbd_device *, int);

sys/dev/usb/uvideo.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvideo.c,v 1.196 2017/12/30 23:08:29 guenther Exp $ */
+/*	$OpenBSD: uvideo.c,v 1.197 2018/04/24 17:22:33 landry Exp $ */
 
 /*
  * Copyright (c) 2008 Robert Nagy <robert@openbsd.org>
@@ -2781,11 +2781,14 @@ int
 uvideo_querycap(void *v, struct v4l2_capability *caps)
 {
 	struct uvideo_softc *sc = v;
+	char vendor[USB_MAX_STRING_LEN];
+	char product[USB_MAX_STRING_LEN];
 
 	bzero(caps, sizeof(*caps));
 	strlcpy(caps->driver, DEVNAME(sc), sizeof(caps->driver));
-	strlcpy(caps->card, "Generic USB video class device",
-	    sizeof(caps->card));
+	usbd_devinfo_vp(sc->sc_udev, vendor, sizeof (vendor), product,
+	    sizeof (product), 0);
+	strlcpy(caps->card, product, sizeof(caps->card));
 	strlcpy(caps->bus_info, "usb", sizeof(caps->bus_info));
 
 	caps->version = 1;