Revert "Drop pre CUDA 11 macro guards in occupancy calculation"

This reverts commit d34c751.

core/src/Cuda/Kokkos_Cuda_BlockSize_Deduction.hpp

@@ -51,7 +51,24 @@ inline int cuda_max_active_blocks_per_sm(cudaDeviceProp const& properties,
                              : max_blocks_regs);
 
   // Limits due to blocks/SM
+#if CUDA_VERSION >= 11000
   int const max_blocks_per_sm = properties.maxBlocksPerMultiProcessor;
+#else
+  int const max_blocks_per_sm = [&properties]() {
+    switch (properties.major) {
+      case 3: return 16;
+      case 5:
+      case 6: return 32;
+      case 7: {
+        int isTuring = properties.minor == 5;
+        return (isTuring) ? 16 : 32;
+      }
+      default:
+        throw_runtime_exception("Unknown device in cuda block size deduction");
+        return 0;
+    }
+  }();
+#endif
 
   // Overall occupancy in blocks
   return std::min({max_blocks_regs, max_blocks_shmem, max_blocks_per_sm});