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/marvell/comphy/phy-comphy-3700.h b/drivers/marvell/comphy/phy-comphy-3700.h
index 714a41c..1628e36 100644
--- a/drivers/marvell/comphy/phy-comphy-3700.h
+++ b/drivers/marvell/comphy/phy-comphy-3700.h
@@ -5,8 +5,8 @@
  * https://spdx.org/licenses
  */
 
-#ifndef _PHY_COMPHY_3700_H
-#define _PHY_COMPHY_3700_H
+#ifndef PHY_COMPHY_3700_H
+#define PHY_COMPHY_3700_H
 
 #define PLL_SET_DELAY_US			600
 #define COMPHY_PLL_TIMEOUT			1000
@@ -255,4 +255,4 @@
 int mvebu_3700_comphy_is_pll_locked(uint8_t comphy_index, uint32_t comphy_mode);
 int mvebu_3700_comphy_power_off(uint8_t comphy_index, uint32_t comphy_mode);
 int mvebu_3700_comphy_power_on(uint8_t comphy_index, uint32_t comphy_mode);
-#endif /* _PHY_COMPHY_3700_H */
+#endif /* PHY_COMPHY_3700_H */