sched_ext: Drop stale entries from the enum lookup tables

The enum lookup tables, enums.autogen.h and enums.autogen.bpf.h, are
maintained by hand despite their names. Five entries name enums the kernel
no longer has. Their lookups in the running kernel's BTF store 0, and
nothing in tools/ uses them. Drop them. No behavior change.

Suggested-by: Andrea Righi <arighi@nvidia.com>
Link: https://lore.kernel.org/all/atr0I5EF7hmM_m7Y@gpd4/
Signed-off-by: Tejun Heo <tj@kernel.org>