ezusb: add dependency to USB

This fixes an error during modpost, when ezusb is built into the kernel
while USB is built as module.

Signed-off-by: René Bürgel <rene.buergel@sohard.de>
Cc: stable <stable@vger.kernel.org>
--
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/misc/Kconfig

@@ -246,6 +246,7 @@ config USB_YUREX
 
 config USB_EZUSB_FX2
 	tristate "Functions for loading firmware on EZUSB chips"
+	depends on USB
 	help
 	  Say Y here if you need EZUSB device support.
 	  (Cypress FX/FX2/FX2LP microcontrollers)