fix(versal-net): correct aff level for cpu off

CPU suspend is calling validate_power_state PSCI opps which returns
power domain state for CPU suspend according to PSTATE type. In case of
power down it assigns PLAT_MAX_OFF_STATE to all affinity level which is
incorrect since for CPU suspend we need to set only MPIDR_AFFLVL0 which
is CPU state. So correct affinity level for CPU suspend.

Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti@amd.com>
Change-Id: I39f92790ea74e4cab8e87342e73e1ac211a46fcd