drm/xe: Enable Fixed CCS mode setting

drm/xe: Enable Fixed CCS mode setting

Disable dynamic HW load balancing of compute resource assignment
to engines and instead enabled fixed mode of mapping compute
resources to engines on all platforms with more than one compute
engine.

By default enable only one CCS engine with all compute slices
assigned to it. This is the desired configuration for common
workloads.

PVC platform supports only the fixed CCS mode (workaround 16016805146).

v2: Rebase, make it platform agnostic
v3: Minor code refactoring

Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>