[PWGLF] Fix compilation warnings (AliceO2Group#8922)

Author: vkucera

PWGMM/Mult/Tasks/dndeta-mft-pbpb.cxx

@@ -1115,7 +1115,7 @@ struct PseudorapidityDensityMFT {
   {
     float c_gen = -1;
     bool atLeastOne = false;
-    int moreThanOne = 0;
+    // int moreThanOne = 0;
     for (auto& collision : collisions) {
       float c_rec = -1;
       if constexpr (C::template contains<aod::CentFT0Cs>()) {
@@ -1132,7 +1132,7 @@ struct PseudorapidityDensityMFT {
           }
         }
         atLeastOne = true;
-        ++moreThanOne;
+        // ++moreThanOne;
         auto z = collision.posZ();
 
         if constexpr (C::template contains<aod::CentFT0Cs>()) {

PWGMM/UE/Tasks/ue-zdc-analysys.cxx

@@ -355,10 +355,11 @@ struct ZDCAnalysis {
     float multFDA = 0;
     float multFDC = 0;
     if (foundBC.has_fdd()) {
-      for (auto amplitude : foundBC.fdd().chargeA()) {
+      auto const& fdd = foundBC.fdd();
+      for (auto const& amplitude : fdd.chargeA()) {
         multFDA += amplitude;
       }
-      for (auto amplitude : foundBC.fdd().chargeC()) {
+      for (auto const& amplitude : fdd.chargeC()) {
         multFDC += amplitude;
       }
     } else {