USB: phy: remove unneeded MODULE_VERSION() usage

MODULE_VERSION is useless for in-kernel drivers, so remove the
use of it in the marvel phy driver, along with the DRIVER_VERSION
define.

Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>