sched_ext: scx_bpf_dispatch_from_dsq_set_*() are allowed from unlocked context

4c30f5ce ("sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()")
added four kfuncs for dispatching while iterating. They are allowed from the
dispatch and unlocked contexts but two of the kfuncs were only added in the
dispatch section. Add missing declarations in the unlocked section.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 4c30f5ce ("sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()")