Fixed vector test failure criteria for conversions

lib/src/phy/utils/test/vector_test.c

@@ -449,7 +449,10 @@ TEST(srslte_vec_convert_fi,
 
   for (int i = 0; i < block_size; i++) {
     gold = (short) ((x[i] * scale));
-      mse += cabsf((float)gold - (float) z[i]);
+    double err = cabsf((float)gold - (float) z[i]);
+    if (err > mse) {
+      mse = err;
+    }
   }
 
   free(x);
@@ -471,7 +474,10 @@ TEST(srslte_vec_convert_if,
 
   for (int i = 0; i < block_size; i++) {
     gold = ((float)x[i]) * k;
-      mse += fabsf(gold - z[i]);
+    double err = cabsf((float)gold - (float) z[i]);
+    if (err > mse) {
+      mse = err;
+    }
   }
 
   free(x);