Fix hit pattern tk layers slhc

HitPattern::trackerLayersWithMeasurement() was broken in SLHC due to hardcoded number of pixel layers in pixelEndcapLayersWithMeasurement.

Fixing the problem and taking the opportunity to add methods to get number of layers/disks with a maximum layer/disk value (so that one can restrict to inner pixels).

If possible put in SLHC12 already.