fixing valid

include/aidge/backend/cpu/operator/MaxPoolingImpl_forward_kernels.hpp

@@ -84,6 +84,7 @@ void MaxPoolingImpl2D_cpu_forward_kernel(const MaxPooling_Op<2>::Parameters &par
 
                                 if (!valid || value > poolValue) {
                                     poolValue = value;
+                                    valid = true;
                                 }
                             }
                         }