[media] staging: se401 depends on USB

Fix build errors by adding "depends on USB":

ERROR: "usb_register_driver" [drivers/staging/se401/se401.ko] undefined!
ERROR: "usb_alloc_urb" [drivers/staging/se401/se401.ko] undefined!
ERROR: "usb_submit_urb" [drivers/staging/se401/se401.ko] undefined!
ERROR: "usb_control_msg" [drivers/staging/se401/se401.ko] undefined!
ERROR: "usb_free_urb" [drivers/staging/se401/se401.ko] undefined!
ERROR: "usb_kill_urb" [drivers/staging/se401/se401.ko] undefined!
ERROR: "usb_deregister" [drivers/staging/se401/se401.ko] undefined!
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/staging/se401/Kconfig

 config USB_SE401
 	tristate "USB SE401 Camera support (DEPRECATED)"
-	depends on VIDEO_DEV && VIDEO_V4L2_COMMON
+	depends on VIDEO_DEV && VIDEO_V4L2_COMMON && USB
 	---help---
 	  Say Y here if you want to connect this type of camera to your
 	  computer's USB port. See <file:Documentation/video4linux/se401.txt>