Limit ofw_cpu_early_foreach to CPUs only

[wma_semihalf.com]

Summary

On some platforms, the /cpus entry contains cpu-to-cluster
map which deffinitely is not a CPU device. Its presence was
causing incrementing of "id" variable and reporting more
CPUs available than it should.
To make "id" valid, increment it only when an entry really
is a CPU.

[andrew]

I'm not sure we need a goto in the loop, finding the next id is simple to do when we know we have a cpu node.

sys/dev/ofw/ofw_cpu.c

300

u_int next_id;
...
next_id = 0;
...
for (child = OF_child(node); child != 0; child = OF_peer(child), id = next_id) {

310

next_id++;

319

Then revert this

329

And this

333

etc.

[andrew]

Just need to fix the minor style issue before committing.

sys/dev/ofw/ofw_cpu.c

300–310

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