Add "#pragma once" in newly created headers

example/ck_tile/18_paged_attention/include/kernel/paged_attention_kernel.hpp

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#pragma once
+
 #include <hip/hip_bf16.h>
 #include "cuda_compat.h"
 

example/ck_tile/18_paged_attention/include/paged_attention.hpp

+#pragma once
+
 #include "kernel/paged_attention_kernel.hpp"
+