net: Add missing annotation for llc_seq_start()

Sparse reports a warning at llc_seq_start()

warning: context imbalance in llc_seq_start() - wrong count at exit
The root cause is the msiing annotation at llc_seq_start()

Add the missing __acquires(RCU) annotation
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/llc/llc_proc.c

@@ -56,7 +56,7 @@ static struct sock *llc_get_sk_idx(loff_t pos)
 	return sk;
 }
 
-static void *llc_seq_start(struct seq_file *seq, loff_t *pos)
+static void *llc_seq_start(struct seq_file *seq, loff_t *pos) __acquires(RCU)
 {
 	loff_t l = *pos;