Remove thread lock critical regions

I tried simply removing the mutex, but it makes the bringUp process fail.

Then I removed it from ringSetup and added it to nodeSetup and finalRingSetup and empirically tried unlocking the mutex as soon as I could without making the process fail. The result I got to is this merge request.

I unfortunately wasn't able to detect any improvements in the ringBringUp process performance with this: it takes about one minute for a setup with one r5560 on ring 0 and one ac701 on ring 3.

It is pretty clear to me that this is because ringSetup is basically a loop around nodeSetup and although ringSetup is not mutex locked, nodeSetup is.

I don't know how to improve this.