tools/sched_ext: scx_qmap: Port to cid-form struct_ops

tools/sched_ext: scx_qmap: Port to cid-form struct_ops

Flip qmap's struct_ops to bpf_sched_ext_ops_cid. The kernel now passes
cids and cmasks to callbacks directly, so the per-callback cpu<->cid
translations that the prior patch added drop out and cpu_ctxs[] is
reindexed by cid. Cpu-form kfunc calls switch to their cid-form
counterparts.

The cpu-only kfuncs (idle/any pick, cpumask iteration) have no cid
substitute. Their callers already moved to cmask scans against
qa_idle_cids and taskc->cpus_allowed in the prior patch, so the kfunc
calls drop here without behavior changes.

set_cmask is wired up via cmask_copy_from_kernel() to copy the
kernel-supplied cmask into the arena-resident taskc cmask. The
cpuperf monitor iterates the cid-form perf kfuncs.

v4: Match scx_bpf_cid_override()'s 2-arg form, drop the shard test
    plumbing, bound nr_cpu_ids for the verifier, and switch mode 3
    from bad-mono to bad-range (Changwoo, Andrea).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Reviewed-by: Changwoo Min <changwoo@igalia.com>
Reviewed-by: Andrea Righi <arighi@nvidia.com>