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/drivers/marvell/mci.h b/include/drivers/marvell/mci.h
index 789b3b9..8ef0234 100644
--- a/include/drivers/marvell/mci.h
+++ b/include/drivers/marvell/mci.h
@@ -7,12 +7,12 @@
 
 /* MCI bus driver for Marvell ARMADA 8K and 8K+ SoCs */
 
-#ifndef _MCI_H_
-#define _MCI_H_
+#ifndef MCI_H
+#define MCI_H
 
 int mci_initialize(int mci_index);
 void mci_turn_link_down(void);
 void mci_turn_link_on(void);
 int mci_get_link_status(void);
 
-#endif /* _MCI_H_ */
+#endif /* MCI_H */