style: split single-line variable declarations

Author: chengleizheng

source/source_estate/elecstate_pw.cpp

@@ -356,7 +356,9 @@ void ElecStatePW<T, Device>::cal_becsum(const psi::Psi<T, Device>& psi)
                 std::vector<T> auxk1_host(nbands * nh_atom);
                 std::vector<T> auxk2_host(nbands * nh_atom);
                 // device buffers allocated once per atom type
-                T *aux_gk = nullptr, *auxk1 = nullptr, *auxk2 = nullptr;
+                T *aux_gk = nullptr;
+		T *auxk1 = nullptr;
+	  	T *auxk2 = nullptr;
                 resmem_complex_op()(auxk1, nbands * nh_atom, "ElecState<PW>::auxk1");
                 resmem_complex_op()(auxk2, nbands * nh_atom, "ElecState<PW>::auxk2");
                 resmem_complex_op()(aux_gk, nh_atom * nh_atom * npol * npol, "ElecState<PW>::aux_gk");