[bugfix] Remove explicit double from SIMD transose code for opcounting

dune/codegen/sumfact/transposereg.hh

@@ -6,7 +6,7 @@
 // DOUBLE 2 x 2
 void transpose_reg(Vec2d& a0, Vec2d& a1)
 {
-  double tmp = a0[1];
+  auto tmp = a0[1];
   a0 = Vec2d(a0[0], a1[0]);
   a1 = Vec2d(tmp, a1[1]);
 }