bc9b178cd0
Reduce code duplication when a bus is subclassed from simplebus by allowing them to call simplebus_attach directly. This is useful when the child bus will just implement the same calls. As not all children will expect to have a ranges property, e.g. the Raspberry Pi firmware, allow this property to be missing. Reviewed by: manu Sponsored by: Innovate UK Differential Revision: https://reviews.freebsd.org/D25925