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/drivers/staging/renesas/rcar/ddr/ddr_a/ddr_init_e3.h b/drivers/staging/renesas/rcar/ddr/ddr_a/ddr_init_e3.h
index 115765b..47fe07b 100644
--- a/drivers/staging/renesas/rcar/ddr/ddr_a/ddr_init_e3.h
+++ b/drivers/staging/renesas/rcar/ddr/ddr_a/ddr_init_e3.h
@@ -4,11 +4,10 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#pragma once
-#include <stdint.h>
+#ifndef DDR_INIT_E3_H
+#define DDR_INIT_E3_H
 
-#ifndef	__DDR_INIT_E3_
-#define	__DDR_INIT_E3_
+#include <stdint.h>
 
 #define RCAR_E3_DDR_VERSION    "rev.0.09"
 
@@ -31,4 +30,4 @@
 #define INITDRAM_ERR_O (0xfffffffe)
 #define INITDRAM_ERR_T (0xfffffff0)
 
-#endif /* __DDR_INIT_E3_ */
+#endif /* DDR_INIT_E3_H */