address of the device identified by its phandle_t by traversing OFW's
device tree. The space and address returned by this function can
subsequently be passed to sparc64_fake_bustag() to construct a valid
tag and handle for use by the newbus I/O functions.
Use of this function is expected to be limited to pre-newbus access to
devices, such as consoles and keyboards.
Partially obtained from: tmm
Reviewed by: jake, jmg, tmm
SBus testing made possible by: jake
Tested with: LINT
2ec1dc3639