Fix MISRA defects in extension libs

No functional changes.

Change-Id: I2f28f20944f552447ac4e9e755493cd7c0ea1192
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/include/lib/extensions/amu_private.h b/include/lib/extensions/amu_private.h
index 0c660bb..ab4e6aa 100644
--- a/include/lib/extensions/amu_private.h
+++ b/include/lib/extensions/amu_private.h
@@ -1,19 +1,19 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __AMU_PRIVATE_H__
-#define __AMU_PRIVATE_H__
+#ifndef AMU_PRIVATE_H
+#define AMU_PRIVATE_H
 
 #include <stdint.h>
 
 uint64_t amu_group0_cnt_read_internal(int idx);
-void amu_group0_cnt_write_internal(int idx, uint64_t);
+void amu_group0_cnt_write_internal(int idx, uint64_t val);
 
 uint64_t amu_group1_cnt_read_internal(int idx);
-void amu_group1_cnt_write_internal(int idx, uint64_t);
+void amu_group1_cnt_write_internal(int idx, uint64_t val);
 void amu_group1_set_evtype_internal(int idx, unsigned int val);
 
-#endif /* __AMU_PRIVATE_H__ */
+#endif /* AMU_PRIVATE_H */