tools/sched_ext: Provide consistent access to scx flags

tools/sched_ext: Provide consistent access to scx flags

Make all the SCX_OPS_* and SCX_PICK_IDLE_* flags available to the
user-space part of the schedulers via the compat interface.

This allows schedulers / selftests to set all the ops flags in
user-space, rather than having them split between BPF and user-space.

Signed-off-by: Andrea Righi <arighi@nvidia.com>
Acked-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>