Fix MPI synchronization issue in get_device_kpar

- Remove redundant probe_gpu_availability check that could cause MPI inconsistency
- Function is only called when device=gpu is already confirmed
- Add comment clarifying the function should only be called in GPU mode

Co-authored-by: dzzz2001 <153698752+dzzz2001@users.noreply.github.com>

Author: Copilot

source/source_base/module_device/device.cpp

@@ -244,13 +244,8 @@ std::string get_device_flag(const std::string &device,
 int get_device_kpar(const int& kpar, const int& bndpar)
 {
 #if __MPI && (__CUDA || __ROCM)
-    // This function should only be called when GPU mode is active
-    // We use probe_gpu_availability to ensure GPU is actually available
-    if (!probe_gpu_availability()) {
-        // If no GPU available, return kpar unchanged
-        return kpar;
-    }
-
+    // This function should only be called when device mode is GPU
+    // The device decision has already been made by get_device_flag()
     int temp_nproc = 0;
     int new_kpar = kpar;
     MPI_Comm_size(MPI_COMM_WORLD, &temp_nproc);