topology: Remove unused cpu_cluster_mask()

topology: Remove unused cpu_cluster_mask()

default_topology[] uses cpu_clustergroup_mask() for the CLS level
(guarded by CONFIG_SCHED_CLUSTER) which is currently provided by x86
(arch/x86/kernel/smpboot.c) and arm64 (drivers/base/arch_topology.c).

Fixes: 1608e70e26d6 ("sched: Add cluster scheduler level in core and related Kconfig for ARM64")
Acked-by: Barry Song <baohua@kernel.org>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20220513093433.425163-1-dietmar.eggemann@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>