Atomic ID of cluster is not robust

[colluca]

The current formulation of the atomic ID breaks if there are more than NrCores non-cluster cores in the system.

snitch_cluster/hw/snitch_cluster/src/snitch_cluster.sv

Lines 1230 to 1233 in 5b2fccd

	// Atomic ID, needs to be unique ID of cluster
	// cluster_id + HartIdOffset + 1 (because 0 is for non-atomic masters)
	assign cluster_user = (core_to_axi_req.q.mask << AtomicIdWidth) |
	((hart_base_id_i / NrCores) + (hart_base_id_i % NrCores) + 1'b1);