bpf: Replace kvfree with kfree for kzalloc memory

These pointers are allocated by kzalloc. Therefore, replace kvfree() with
kfree() to avoid unnecessary is_vmalloc_addr() check in kvfree(). This is
the remaining unmodified part from [1].

Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20250811123949.552885-1-rongqianfeng@vivo.com [1]
Link: https://lore.kernel.org/bpf/20250827032812.498216-1-yangfeng59949@163.com

Author: kknjh

kernel/bpf/verifier.c

@@ -2021,7 +2021,7 @@ static void free_backedges(struct bpf_scc_visit *visit)
 	for (backedge = visit->backedges; backedge; backedge = next) {
 		free_verifier_state(&backedge->state, false);
 		next = backedge->next;
-		kvfree(backedge);
+		kfree(backedge);
 	}
 	visit->backedges = NULL;
 }
@@ -19651,7 +19651,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
 	err = maybe_enter_scc(env, new);
 	if (err) {
 		free_verifier_state(new, false);
-		kvfree(new_sl);
+		kfree(new_sl);
 		return err;
 	}