block: pg: add header include guard

Add a header include guard just in case.

Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

Author: masahir0y

include/uapi/linux/pg.h

@@ -35,6 +35,9 @@
 
 */
 
+#ifndef _UAPI_LINUX_PG_H
+#define _UAPI_LINUX_PG_H
+
 #define PG_MAGIC	'P'
 #define PG_RESET	'Z'
 #define PG_COMMAND	'C'
@@ -61,4 +64,4 @@ struct pg_read_hdr {
 
 };
 
-/* end of pg.h */
+#endif /* _UAPI_LINUX_PG_H */