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/plat/rockchip/rk3399/drivers/dram/dram_spec_timing.h b/plat/rockchip/rk3399/drivers/dram/dram_spec_timing.h
index 30d3aea..9cda22c 100644
--- a/plat/rockchip/rk3399/drivers/dram/dram_spec_timing.h
+++ b/plat/rockchip/rk3399/drivers/dram/dram_spec_timing.h
@@ -4,8 +4,9 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef _DRAM_SPEC_TIMING_HEAD_
-#define _DRAM_SPEC_TIMING_HEAD_
+#ifndef DRAM_SPEC_TIMING_H
+#define DRAM_SPEC_TIMING_H
+
 #include <stdint.h>
 
 enum ddr3_speed_rate {
@@ -503,4 +504,4 @@
 void dram_get_parameter(struct timing_related_config *timing_config,
 			struct dram_timing_t *pdram_timing);
 
-#endif /* _DRAM_SPEC_TIMING_HEAD_ */
+#endif /* DRAM_SPEC_TIMING_H */