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>

Both Cortex-A75 and Cortex-A55 CPUs use the ARM DynamIQ Shared Unit
(DSU). The power-down and power-up sequences are therefore mostly
managed in hardware, and required software operations are considerably
simpler.

Change-Id: I68b30e6e1ebe7c041d5e67f39c59f08575fc7ecc
Co-authored-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>