bpf: drop kthread_exit from noreturn_deny

commit 7fe44c4 upstream.

kthread_exit became a macro to do_exit in commit 28aaa9c
("kthread: consolidate kthread exit paths to prevent use-after-free"),
so there is no kthread_exit function BTF ID to resolve. Remove it from
noreturn_deny to avoid resolve_btfids unresolved symbol warnings.

Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: cloehle

kernel/bpf/verifier.c

@@ -24081,7 +24081,6 @@ BTF_ID(func, __x64_sys_exit_group)
 BTF_ID(func, do_exit)
 BTF_ID(func, do_group_exit)
 BTF_ID(func, kthread_complete_and_exit)
-BTF_ID(func, kthread_exit)
 BTF_ID(func, make_task_dead)
 BTF_SET_END(noreturn_deny)