bus_alloc_resource: First step in passing resource IDs by value

Add wrapper inline functions for bus_alloc_resource* that accept a
resource ID by value (instead of a pointer). The rest of the bus
resource API (outside of compat shims) does not accept resource IDs as
arguments, but instead obtains the resource ID from the resource
itself when needed. As such, there is no reason to return any
potentially modified resource IDs to the caller.

Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D53401

(cherry picked from commit 7eb213614b90cde31707a53c4b8ae6acacf2aa0f)