Enforce full include path for includes. Deprecate old paths.

The following folders inside include/lib have been left unchanged:

- include/lib/cpus/${ARCH}
- include/lib/el3_runtime/${ARCH}

The reason for this change is that having a global namespace for
includes isn't a good idea. It defeats one of the advantages of having
folders and it introduces problems that are sometimes subtle (because
you may not know the header you are actually including if there are two
of them).

For example, this patch had to be created because two headers were
called the same way: e0ea0928d5b7 ("Fix gpio includes of mt8173 platform
to avoid collision."). More recently, this patch has had similar
problems: 46f9b2c3a282 ("drivers: add tzc380 support").

This problem was introduced in commit 4ecca33988b9 ("Move include and
source files to logical locations"). At that time, there weren't too
many headers so it wasn't a real issue. However, time has shown that
this creates problems.

Platforms that want to preserve the way they include headers may add the
removed paths to PLAT_INCLUDES, but this is discouraged.

Change-Id: I39dc53ed98f9e297a5966e723d1936d6ccf2fc8f
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

When HW_ASSISTED_COHERENCY is enabled we can use spinlocks
instead of using the more complex and slower bakery algorithm.

Change-Id: I9d791a70050d599241169b9160a67e57d5506564
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>

Currently the SCMI driver supports MHUv1, but Arm platforms may have
varied versions of MHU driver, with MHUv2 controllers being in the
latest Arm platforms.

This patch updates the SCMI driver to support MHUv2, specifically that
the sender must send the wake-up to the receiver before initiating any
data transfer.

Also, the existing mhu driver files, css_mhu.c and css_mhu.h, have been
moved from the scpi directory to a new directory, css/drivers/mhu.

Change-Id: I9b46b492a3e1d9e26db12d83a9773958a8c8402f
Signed-off-by: Samarth Parikh <samarth.parikh@arm.com>

This patch adds the SCMI driver for communicating with SCP. The power
domain management and system power management protocol of the SCMI
specification[1] is implemented in the driver. The SCP power management
abstraction layer for SCMI for CSS power management is also added.

A new buid option `CSS_USE_SCMI_DRIVER` is introduced to select SCMI
driver over SCPI.

[1] ARM System Control and Management Interface v1.0 (SCMI)
Document number: ARM DEN 0056A

Change-Id: I67265615a17e679a2afe810b9b0043711ba09dbb
Signed-off-by: Soby Mathew <soby.mathew@arm.com>