In order to prepare low power use cases, functions are added to manage
the entry or exit of DDR from self-refresh mode.

Change-Id: I8a1cbc48d613366fca69b4fc6870e53f8b917598
Signed-off-by: Yann Gautier <yann.gautier@st.com>

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>

The DDR driver is under dual license, BSD and GPLv2.
The configuration parameters are taken from device tree.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Nicolas Le Bayon <nicolas.le.bayon@st.com>
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>