net: don't include ndisc.h from ipv6.h

Nothing in ipv6.h needs ndisc.h, drop it.

Link: https://lore.kernel.org/r/[e-mail]
Acked-by: Jeremy Kerr <[e-mail]>
Acked-by: Stefan Schmidt <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: David Ahern <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/bonding/bond_alb.c

···
 #include <linux/in.h>
 #include <net/arp.h>
 #include <net/ipv6.h>
+#include <net/ndisc.h>
 #include <asm/byteorder.h>
 #include <net/bonding.h>
 #include <net/bond_alb.h>

drivers/net/usb/cdc_mbim.c

···
 #include <net/ipv6.h>
 #include <net/addrconf.h>
 #include <net/ipv6_stubs.h>
+#include <net/ndisc.h>
 
 /* alternative VLAN for IP session 0 if not untagged */
 #define MBIM_IPS0_VID	4094

include/net/ipv6.h

···
 #include <linux/refcount.h>
 #include <linux/jump_label_ratelimit.h>
 #include <net/if_inet6.h>
-#include <net/ndisc.h>
 #include <net/flow.h>
 #include <net/flow_dissector.h>
 #include <net/snmp.h>

include/net/ipv6_frag.h

···
 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _IPV6_FRAG_H
 #define _IPV6_FRAG_H
+#include <linux/icmpv6.h>
 #include <linux/kernel.h>
 #include <net/addrconf.h>
 #include <net/ipv6.h>

net/6lowpan/core.c

···
  * (C) 2015 Pengutronix, Alexander Aring <[e-mail]>
  */
 
+#include <linux/if_arp.h>
 #include <linux/module.h>
 
 #include <net/6lowpan.h>

net/ieee802154/6lowpan/core.c

···
 #include <linux/module.h>
 #include <linux/netdevice.h>
 #include <linux/ieee802154.h>
+#include <linux/if_arp.h>
 
 #include <net/ipv6.h>
 

net/mctp/device.c

···
  * Copyright (c) 2021 Google
  */
 
+#include <linux/if_arp.h>
 #include <linux/if_link.h>
 #include <linux/mctp.h>
 #include <linux/netdevice.h>