Suppress host/device usage warning (#2192)

This pragma is a workaround for cudf build issues, see e.g. https://github.com/rapidsai/cudf/actions/runs/20384141895/job/58581416851?pr=20929. The thrust allocator class needs to be reworked eventually anyway due to the upstream allocator being deprecated, so this workaround is acceptable for now. I'm entirely confused as to why this line is where the suppression is needed and I suspect that this is a completely false diagnostic from nvcc, but for now I think it's acceptable to add this as a workaround to get builds passing. I verified that this fixes cudf builds in a local devcontainer reproducing the issue.

Authors:
  - Vyas Ramasubramani (https://github.com/vyasr)

Approvers:
  - Bradley Dice (https://github.com/bdice)

URL: #2192

Author: vyasr

cpp/include/rmm/detail/runtime_capabilities.hpp

@@ -84,6 +84,11 @@ struct export_handle_type {
  * @return true if supported
  * @return false if unsupported
  */
+#ifdef __CUDACC__
+// This suppression was needed due to a false positive warning from nvcc. We
+// should be able to remove it altogether once we rework the thrust allocator.
+#pragma nv_diag_suppress 20011
+#endif
 struct hwdecompress {
   static bool is_supported()
   {
@@ -100,6 +105,9 @@ struct hwdecompress {
 #endif
   }
 };
+#ifdef __CUDACC__
+#pragma nv_diag_default 20011
+#endif
 
 /**
  * @brief Check if the current device supports concurrent managed access.