[PARISC] Unbreak processor_probe when we have more than NR_CPUS

If we already have NR_CPUS worth of cpus online, we obviously shouldn't
be trying to bring up more... Fixes a particularly vexing issue I had when
running another machines kernel on my rp3440.

Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
1 file changed