Staging: media: go7007: use module_usb_driver()

There is no need to initialize a static array to NULL at startup, so we
can use the module_usb_driver() call for the go7007 module.

Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>