[DPG] Fix compilation warnings (AliceO2Group#8915)

Author: vkucera

DPG/Tasks/AOTTrack/PID/TPC/qaPIDTPCSignal.cxx

@@ -171,7 +171,7 @@ struct tpcPidQaSignal {
       return false;
     }
     histos.fill(HIST("trksel"), 6);
-    if (pidInTracking != -1 && (track.pidForTracking() != std::abs(pidInTracking))) {
+    if (pidInTracking != -1 && (track.pidForTracking() != static_cast<unsigned int>(std::abs(pidInTracking)))) {
       return false;
     }
     histos.fill(HIST("trksel"), 7);

DPG/Tasks/AOTTrack/qaEfficiency.cxx

@@ -2073,8 +2073,8 @@ struct QaEfficiency {
       float trackEta = track.eta();
       float trackPhi = track.phi();
       float trackSign = track.sign();
-      float occupancy;
-      float centrality;
+      float occupancy{};
+      float centrality{};
       if (doOccupancy) {
         centrality = collision.centFT0C();
         if (useFT0OccEstimator) {

DPG/Tasks/AOTTrack/qaEventTrack.cxx

@@ -1618,7 +1618,7 @@ void qaEventTrack::fillRecoHistogramsGroupedTracks(const C& collision, const T&
           sign = pdgInfo->Charge() / abs(pdgInfo->Charge());
         }
         // resolution plots
-        if (doExtraPIDqa && track.pidForTracking() != std::abs(PartIdentifier)) {
+        if (doExtraPIDqa && track.pidForTracking() != static_cast<unsigned int>(std::abs(PartIdentifier))) {
           // full eta range
           histos.fill(HIST("Tracks/Kine/resoPtVsptmcWrongPIDinTrk"), track.pt() - particle.pt(), particle.pt());
           histos.fill(HIST("Tracks/Kine/resoPtVsptmcScaledWrongPIDinTrk"), (track.pt() - particle.pt()) / particle.pt(), particle.pt());
@@ -1651,7 +1651,7 @@ void qaEventTrack::fillRecoHistogramsGroupedTracks(const C& collision, const T&
         }
 
         // optionally check for PID in tracking: select tracks with correct PID in tracking
-        if (checkPIDforTracking && track.pidForTracking() != std::abs(PartIdentifier)) {
+        if (checkPIDforTracking && track.pidForTracking() != static_cast<unsigned int>(std::abs(PartIdentifier))) {
           continue;
         }