bfqio: Use pragma once for include guard

Change-Id: I53a8ee558beeb115fa08905a8dc2cda64c1d2de5
diff --git a/libbfqio/include/bfqio/bfqio.h b/libbfqio/include/bfqio/bfqio.h
index eebd66e..14392d9 100644
--- a/libbfqio/include/bfqio/bfqio.h
+++ b/libbfqio/include/bfqio/bfqio.h
@@ -14,8 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef __BFQIO_H
-#define __BFQIO_H
+#pragma once
 
 #ifdef __cplusplus
 extern "C" {
@@ -26,5 +25,3 @@
 #ifdef __cplusplus
 }
 #endif
-
-#endif /* __BFQIO_H */