greybus: call put_device() on error

As soon as we've called device_initialize() we're required to call
put_device() in order to drop our reference to the device structure.
This was missed in the error path in greybus_new_module().  Fix that.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>