Sanitise includes across codebase ...

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>

coreboot: Add support for CBMEM console ...

coreboot supports an in-memory console to store firmware logs even when
no serial console is available. It is widely supported by
coreboot-compatible bootloaders (including SeaBIOS and GRUB) and can be
read by the Linux kernel.

This patch allows BL31 to add its own log messages to this console. The
driver will be registered automatically if coreboot support is compiled
in and detects the presence of a console buffer in the coreboot tables.

Change-Id: I31254dfa0c2fdeb7454634134b5707b4b4154907
Signed-off-by: Julius Werner <jwerner@chromium.org>

Add platform-independent coreboot support library ...

This patch adds the foundation for a platform-independent coreboot
support library that can be shared by all platforms that boot BL31 from
coreboot (acting as BL2). It adds code to parse the "coreboot table", a
data structure that coreboot uses to communicate different kinds of
information to later-stage firmware and certain OS drivers.

As a first small use case for this information, allow platforms to
access the serial console configuration used by coreboot, removing the
need to hardcode base address and divisors and allowing Trusted Firmware
to benefit from coreboot's user configuration (e.g. which UART to pick
and which baud rate to use).

Change-Id: I2bfb39cd2609ce6640b844ab68df6c9ae3f28e9e
Signed-off-by: Julius Werner <jwerner@chromium.org>