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/plat/marvell/common/marvell_pm.h b/include/plat/marvell/common/marvell_pm.h
index 2817a46..8f16607 100644
--- a/include/plat/marvell/common/marvell_pm.h
+++ b/include/plat/marvell/common/marvell_pm.h
@@ -5,8 +5,8 @@
  * https://spdx.org/licenses
  */
 
-#ifndef _MARVELL_PM_H_
-#define _MARVELL_PM_H_
+#ifndef MARVELL_PM_H
+#define MARVELL_PM_H
 
 #define MVEBU_MAILBOX_MAGIC_NUM		PLAT_MARVELL_MAILBOX_MAGIC_NUM
 #define MVEBU_MAILBOX_SUSPEND_STATE	0xb007de7c
@@ -23,4 +23,4 @@
 /* BLE execution start counter value */
 #define	MBOX_IDX_START_CNT		4
 
-#endif /* _MARVELL_PM_H_ */
+#endif /* MARVELL_PM_H */