mISDN: Fix a sleep-in-atomic bug

The driver may sleep under a read spin lock, and the function call path is:
send_socklist (acquire the lock by read_lock)
skb_copy(GFP_KERNEL) --> may sleep

To fix it, the "GFP_KERNEL" is replaced with "GFP_ATOMIC".

Signed-off-by: Jia-Ju Bai <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/isdn/mISDN/stack.c

···
 		if (sk->sk_state != MISDN_BOUND)
 			continue;
 		if (!cskb)
-			cskb = skb_copy(skb, GFP_KERNEL);
+			cskb = skb_copy(skb, GFP_ATOMIC);
 		if (!cskb) {
 			printk(KERN_WARNING "%s no skb\n", __func__);
 			break;