Standardise header guards across codebase

All identifiers, regardless of use, that start with two underscores are
reserved. This means they can't be used in header guards.

The style that this project is now to use the full name of the file in
capital letters followed by 'H'. For example, for a file called
"uart_example.h", the header guard is UART_EXAMPLE_H.

The exceptions are files that are imported from other projects:

- CryptoCell driver
- dt-bindings folders
- zlib headers

Change-Id: I50561bf6c88b491ec440d0c8385c74650f3c106e
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/include/bl31/bl31.h b/include/bl31/bl31.h
index 7c35922..08c555d 100644
--- a/include/bl31/bl31.h
+++ b/include/bl31/bl31.h
@@ -4,8 +4,8 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __BL31_H__
-#define __BL31_H__
+#ifndef BL31_H
+#define BL31_H
 
 #include <stdint.h>
 
@@ -21,4 +21,4 @@
 void bl31_main(void);
 void bl31_lib_init(void);
 
-#endif /* __BL31_H__ */
+#endif /* BL31_H */
diff --git a/include/bl31/ea_handle.h b/include/bl31/ea_handle.h
index 060c9b7..68f012c 100644
--- a/include/bl31/ea_handle.h
+++ b/include/bl31/ea_handle.h
@@ -4,8 +4,8 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __EA_HANDLE_H__
-#define __EA_HANDLE_H__
+#ifndef EA_HANDLE_H
+#define EA_HANDLE_H
 
 /* Constants indicating the reason for an External Abort */
 
@@ -21,4 +21,4 @@
 /* RAS event signalled as peripheral interrupt */
 #define ERROR_INTERRUPT		3
 
-#endif /* __EA_HANDLE_H__ */
+#endif /* EA_HANDLE_H */
diff --git a/include/bl31/interrupt_mgmt.h b/include/bl31/interrupt_mgmt.h
index 0cdbda0..6a49fb6 100644
--- a/include/bl31/interrupt_mgmt.h
+++ b/include/bl31/interrupt_mgmt.h
@@ -4,8 +4,8 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __INTERRUPT_MGMT_H__
-#define __INTERRUPT_MGMT_H__
+#ifndef INTERRUPT_MGMT_H
+#define INTERRUPT_MGMT_H
 
 #include <arch.h>
 #include <utils_def.h>
@@ -144,4 +144,4 @@
 int enable_intr_rm_local(uint32_t type, uint32_t security_state);
 
 #endif /*__ASSEMBLY__*/
-#endif /* __INTERRUPT_MGMT_H__ */
+#endif /* INTERRUPT_MGMT_H */