L1: Fix unused variable warning.

reco/L1/CbmL1.h

@@ -181,7 +181,7 @@ public:
   void ApplyCorrectionToMaterialMap(L1Material& material, const L1MaterialInfo& homogenious)
   {
     // TODO: unify the correction function for all detectors
-    float minVal = 0.;
+    [[maybe_unused]] float minVal = 0.;
     if constexpr (detID == L1DetectorID::kMuch) { minVal = 0.15f; }
     else if constexpr (detID == L1DetectorID::kTof || detID == L1DetectorID::kTrd) {
       minVal = 0.0015f;