To support platforms which are based on multi-threaded CPUs, override
the weak implementation of plat_arm_get_cpu_pe_count function to return
the number of threads supported by the CPU used in the platform.

Change-Id: Ia680773f1277b17e2d3d2414d87943dcece33e89
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>

On SGI platforms, the interconnect is setup by the SCP and so the
existing unused interconnect setup in sgi575 platform code can be
removed. As a result of this, sgi_plat_config.c and sgi_bl1_setup.c
files can be removed as these files are now empty or can be
substainated by the existing weak functions.

Change-Id: I3c883e4d1959d890bf2213a9be01f02551ea3a45
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>

The Arm SGI platforms can switch to using SCMI. So enable support for
SCMI and remove portions of code that would be unused after switching
to SCMI.

Change-Id: Ifd9e1c944745f703da5f970b5daf1be2b07ed14e
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>

The MT bit in MPIDR is always set for SGI platforms and so the
core position calculation code is updated to take into account
the thread affinity value as well.

Change-Id: I7b2a52707f607dc3859c6bbcd2b145b7987cb4ed
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
Signed-off-by: Vishwanatha HG <vishwanatha.hg@arm.com>

Add support for System Guidance for Infrastructure platform SGI575.

Change-Id: I0125c2ed4469fbc8367dafcc8adce770b6b3147d
Signed-off-by: Nariman Poushin <nariman.poushin@linaro.org>