powerpc/prom: early_init_dt_scan_cpus() updates cpu features only once
powerpc/prom: early_init_dt_scan_cpus() updates cpu features only once

All our cpu feature updates were done for every CPU in the device-tree,
thus overwriting the cputable bits over and over again. Instead do them
only for the boot CPU.

Signed-off-by: Benjamin Herrenschmidt <a7089bb6e7e92505d88aaff006cbdd60cc9120b6@kernel.crashing.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs