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/mvebu.h b/include/plat/marvell/common/mvebu.h
index a7d6c3f..35a0200 100644
--- a/include/plat/marvell/common/mvebu.h
+++ b/include/plat/marvell/common/mvebu.h
@@ -5,8 +5,8 @@
  * https://spdx.org/licenses
  */
 
-#ifndef _MVEBU_H_
-#define _MVEBU_H_
+#ifndef MVEBU_H
+#define MVEBU_H
 
 /* Use this functions only when printf is allowed */
 #define debug_enter()	VERBOSE("----> Enter %s\n", __func__)
@@ -36,4 +36,4 @@
 #define _1GB_				(_1MB_ * 1024ULL)
 #define _2GB_				(2 * _1GB_)
 
-#endif	/* MVEBU_H */
+#endif /* MVEBU_H */