Some cores support only AArch64 mode. In those cores, only a limited
subset of the AArch32 system registers are implemented. Hence, if TF-A
is supposed to run on AArch64-only cores, it must be compiled with
CTX_INCLUDE_AARCH32_REGS=0.

Currently, the default settings for compiling TF-A are with the AArch32
system registers included. So, if we compile TF-A the default way and
attempt to run it on an AArch64-only core, we only get a runtime panic.

Now a compile-time check has been added to ensure that this flag has the
appropriate value when AArch64-only cores are included in the build.

Change-Id: I298ec550037fafc9347baafb056926d149197d4c
Signed-off-by: John Tsichritzis <john.tsichritzis@arm.com>

This patch fixes this issue:
https://github.com/ARM-software/tf-issues/issues/660

The introduced changes are the following:

1) Some cores implement cache coherency maintenance operation on the
hardware level. For those cores, such as - but not only - the DynamIQ
cores, it is mandatory that TF-A is compiled with the
HW_ASSISTED_COHERENCY flag. If not, the core behaviour at runtime is
unpredictable. To prevent this, compile time checks have been added and
compilation errors are generated, if needed.

2) To enable this change for FVP, a logical separation has been done for
the core libraries. A system cannot contain cores of both groups, i.e.
cores that manage coherency on hardware and cores that don't do it. As
such, depending on the HW_ASSISTED_COHERENCY flag, FVP includes the
libraries only of the relevant cores.

3) The neoverse_e1.S file has been added to the FVP sources.

Change-Id: I787d15819b2add4ec0d238249e04bf0497dc12f3
Signed-off-by: John Tsichritzis <john.tsichritzis@arm.com>

Change-Id: I0a81f4ea94d41245cd5150de341b51fc70babffe
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>