plat/arm: Fix MISRA defects in SiP SVC handler

No functional changes.

Change-Id: I9b9f8d3dfde08d57706ad5450de6ff858a55ac01
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/include/plat/arm/common/plat_arm.h b/include/plat/arm/common/plat_arm.h
index bdcb144..e7082d0 100644
--- a/include/plat/arm/common/plat_arm.h
+++ b/include/plat/arm/common/plat_arm.h
@@ -3,8 +3,8 @@
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
-#ifndef __PLAT_ARM_H__
-#define __PLAT_ARM_H__
+#ifndef PLAT_ARM_H
+#define PLAT_ARM_H
 
 #include <bakery_lock.h>
 #include <cassert.h>
@@ -292,4 +292,4 @@
 extern const mmap_region_t plat_arm_mmap[];
 extern const unsigned int arm_pm_idle_states[];
 
-#endif /* __PLAT_ARM_H__ */
+#endif /* PLAT_ARM_H */