qemu/aarch64/plat_helpers.S : calculate the position shift

Rather than re-create this file in multiple qemu variants instead
caclulate the shift needed to convert MPIDR to position.

Add a new PLATFORM_CPU_PER_CLUSTER_SHIFT define in platform_def.h
for both qemu and qemu_sbsa to enable this calculation.

Signed-off-by: Graeme Gregory <graeme@nuviainc.com>
Change-Id: I0e3a86354aa716d95150a3a34b15287cd70c8fd2
3 files changed