ppdev: fix memory leak

The variable name was only released if parport_register_dev_model()
fails. Now that we are using the device-model the parport driver
will duplicate the name and use it. So we can release the variable
after the device has been registered with the parport.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>