WMI: return error if wmi_create_device() fails

The break resets the retval to 0 but we want to return an error code.
This was introduced in c64eefd48c4 "WMI: embed struct device directly
into wmi_block"

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>