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>

Map the initialization code for BL31 to overlap with the memory
required for the secondary cores stack. Once BL31 has been
initialized the memory can be remapped to RW data so that it can
be used for secondary cores stacks. By moving code from .text to
.text.init the size of the BL31 image is decreased by a page.

Split arm_common.ld.S into two linker scripts, one for tzc_dram
(arm_tzc_dram.ld.S) and one for reclaiming initialization code
(arm_reclaim_init.ld.S) so that platforms can chose which memory
regions they wish to include.

Change-Id: I648e88f3eda1aa71765744cf34343ecda9320b32
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>