Fail to probe on simplebus nodes that lack a "ranges" property.

Increasingly, FDT data has the "simple-bus" compatible string on nodes
that have children, but we wouldn't consider them to be busses.  If the
node lacks a ranges property then we will fail to attach successfully,
so fail to probe as well.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@273282 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f