lib.pmu: Fixed bug that required affinity to CPU core 0
lib.pmu: Fixed bug that required affinity to CPU core 0

This fixes a bug where lib.pmu only works when you have affinity to
CPU core 0. I did not catch this because I habitually test with
'taskset -c 0 ...'.

Now lib.pmu requires only that you have affinity to one specific core
(regardless of which core that is).

Credit to Alexander Nasonov.
(cherry picked from commit 43eda0fc4918c9471464ecf9d14a7e1ed76d06c4)

SnabbCo/snabbswitch,lukego/snabbswitch,heryii/snabb,eugeneia/snabb,justincormack/snabbswitch,kbara/snabb,Igalia/snabbswitch,mixflowtech/logsensor,dpino/snabb,Igalia/snabbswitch,aperezdc/snabbswitch,snabbco/snabb,kbara/snabb,wingo/snabb,mixflowtech/logsensor,eugeneia/snabb,lukego/snabb,dpino/snabb,snabbnfv-goodies/snabbswitch,alexandergall/snabbswitch,aperezdc/snabbswitch,Igalia/snabb,hb9cwp/snabbswitch,dpino/snabb,eugeneia/snabb,justincormack/snabbswitch,dpino/snabbswitch,lukego/snabbswitch,heryii/snabb,wingo/snabb,alexandergall/snabbswitch,dpino/snabb,mixflowtech/logsensor,SnabbCo/snabbswitch,alexandergall/snabbswitch,dpino/snabbswitch,lukego/snabbswitch,snabbco/snabb,Igalia/snabb,plajjan/snabbswitch,eugeneia/snabb,andywingo/snabbswitch,kbara/snabb,kbara/snabb,aperezdc/snabbswitch,lukego/snabb,wingo/snabb,snabbnfv-goodies/snabbswitch,snabbco/snabb,wingo/snabbswitch,wingo/snabbswitch,snabbco/snabb,kbara/snabb,eugeneia/snabbswitch,dpino/snabbswitch,kbara/snabb,snabbco/snabb,Igalia/snabb,eugeneia/snabbswitch,eugeneia/snabb,mixflowtech/logsensor,dpino/snabb,alexandergall/snabbswitch,heryii/snabb,mixflowtech/logsensor,hb9cwp/snabbswitch,plajjan/snabbswitch,lukego/snabb,snabbnfv-goodies/snabbswitch,SnabbCo/snabbswitch,eugeneia/snabb,Igalia/snabb,Igalia/snabbswitch,Igalia/snabbswitch,aperezdc/snabbswitch,alexandergall/snabbswitch,alexandergall/snabbswitch,snabbco/snabb,eugeneia/snabbswitch,lukego/snabbswitch,Igalia/snabb,lukego/snabb,andywingo/snabbswitch,eugeneia/snabbswitch,heryii/snabb,dpino/snabb,wingo/snabb,andywingo/snabbswitch,justincormack/snabbswitch,wingo/snabb,hb9cwp/snabbswitch,snabbco/snabb,Igalia/snabb,heryii/snabb,heryii/snabb,dpino/snabbswitch,wingo/snabbswitch,Igalia/snabb,wingo/snabbswitch,alexandergall/snabbswitch,hb9cwp/snabbswitch,eugeneia/snabb,SnabbCo/snabbswitch,justincormack/snabbswitch,plajjan/snabbswitch,snabbco/snabb,Igalia/snabb,wingo/snabb,andywingo/snabbswitch,snabbnfv-goodies/snabbswitch,alexandergall/snabbswitch,eugeneia/snabb,Igalia/snabbswitch,dpino/snabb,plajjan/snabbswitch