sched_ext: Merge branch 'for-6.14-fixes' into for-6.15

Pull for-6.14-fixes to receive:

  9360dfe4 ("sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl()")

which conflicts with:

  337d1b35 ("sched_ext: Move built-in idle CPU selection policy to a separate file")

Signed-off-by: Tejun Heo <tj@kernel.org>