greybus: fix a leak on error in gb_module_create()

We should release ->interfaces[0] as well.

Fixes: b15d97d7

 ("greybus: core: add module abstraction")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>