suppress fallthrouth warning

Device/Coord/CoordSystem2D.cpp

@@ -158,6 +158,7 @@ double SphericalCoords::calculateValue(size_t i_axis, Coords units, double value
             return (k_f - k_i).z();
         }
         ASSERT(0);
+        return 0;
     }
     case Coords::QXQY: {
         const R3 k_i = vecOfLambdaAlphaPhi(m_wavelength, m_alpha_i, m_phi_i);
@@ -170,6 +171,7 @@ double SphericalCoords::calculateValue(size_t i_axis, Coords units, double value
             return (k_f - k_i).x();
         }
         ASSERT(0);
+        return 0;
     }
     default:
         ASSERT(0);