Initial Deferred Procedure Call (DPC) support

sdk/xtdk/xtstruct.h

@@ -39,6 +39,7 @@ typedef enum _EFI_UART_PARITY_TYPE EFI_UART_PARITY_TYPE, *PEFI_UART_PARITY_TYPE;
 typedef enum _EFI_UART_STOP_BITS_TYPE EFI_UART_STOP_BITS_TYPE, *PEFI_UART_STOP_BITS_TYPE;
 typedef enum _EFI_UNIVERSA_GRAPHICS_BLT_OPERATION EFI_UNIVERSA_GRAPHICS_BLT_OPERATION, *PEFI_UNIVERSA_GRAPHICS_BLT_OPERATION;
 typedef enum _KAPC_ENVIRONMENT KAPC_ENVIRONMENT, *PKAPC_ENVIRONMENT;
+typedef enum _KDPC_IMPORTANCE KDPC_IMPORTANCE, *PKDPC_IMPORTANCE;
 typedef enum _KOBJECTS KOBJECTS, *PKOBJECTS;
 typedef enum _KPROCESS_STATE KPROCESS_STATE, *PKPROCESS_STATE;
 typedef enum _KTHREAD_STATE KTHREAD_STATE, *PKTHREAD_STATE;