fix a compilation bug

Author: dzzz2001

source/module_hsolver/kernels/cuda/diag_cusolver.cu

@@ -5,7 +5,7 @@
 
 Diag_Cusolver_gvd::Diag_Cusolver_gvd(){
 // step 1: create cusolver/cublas handle
-#ifdef __MPI
+#if defined(__MPI) && defined(__CUDA)
     device_id = base_device::information::set_device_by_rank();
     checkCudaErrors( cudaSetDevice(device_id) );
 #endif