bpf: remove redundant variable old_flags

Variable old_flags is being assigned but is never read; it is redundant
and can be removed.

Cleans up clang warning: Value stored to 'old_flags' is never read
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

kernel/bpf/cgroup.c

@@ -192,7 +192,6 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
 	struct cgroup_subsys_state *css;
 	struct bpf_prog_list *pl;
 	bool pl_was_allocated;
-	u32 old_flags;
 	int err;
 
 	if ((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI))
@@ -239,7 +238,6 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
 		pl->prog = prog;
 	}
 
-	old_flags = cgrp->bpf.flags[type];
 	cgrp->bpf.flags[type] = flags;
 
 	/* allocate and recompute effective prog arrays */