ALSA: asihpi - Add include guard.

Signed-off-by: Eliot Blennerhassett <eblennerhassett@audioscience.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/asihpi/hpimsginit.h b/sound/pci/asihpi/hpimsginit.h
index 864ad02..bfd330d 100644
--- a/sound/pci/asihpi/hpimsginit.h
+++ b/sound/pci/asihpi/hpimsginit.h
@@ -21,11 +21,15 @@
  (C) Copyright AudioScience Inc. 2007
 *******************************************************************************/
 /* Initialise response headers, or msg/response pairs.
-Note that it is valid to just init a response e.g. when a lower level is preparing
-a response to a message.
-However, when sending a message, a matching response buffer always must be prepared
+Note that it is valid to just init a response e.g. when a lower level is
+preparing a response to a message.
+However, when sending a message, a matching response buffer must always be
+prepared.
 */
 
+#ifndef _HPIMSGINIT_H_
+#define _HPIMSGINIT_H_
+
 void hpi_init_response(struct hpi_response *phr, u16 object, u16 function,
 	u16 error);
 
@@ -38,3 +42,5 @@
 void hpi_init_message_responseV1(struct hpi_message_header *phm, u16 msg_size,
 	struct hpi_response_header *phr, u16 res_size, u16 object,
 	u16 function);
+
+#endif				/* _HPIMSGINIT_H_ */