igmp: remove exceptional & on function name

In this file, function names are otherwise used as pointers without &.

A simplified version of the Coccinelle semantic patch that makes this
change is as follows:

// <smpl>
@r@
identifier f;
@@

f(...) { ... }

@@
identifier r.f;
@@

- &f
+ f
// </smpl>
Signed-off-by: NHimangi Saraogi <himangi774@gmail.com>
Acked-by: NJulia Lawall <julia.lawall@lip6.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/igmp.c

@@ -1321,7 +1321,7 @@ void ip_mc_inc_group(struct in_device *in_dev, __be32 addr)
 	atomic_set(&im->refcnt, 1);
 	spin_lock_init(&im->lock);
 #ifdef CONFIG_IP_MULTICAST
-	setup_timer(&im->timer, &igmp_timer_expire, (unsigned long)im);
+	setup_timer(&im->timer, igmp_timer_expire, (unsigned long)im);
 	im->unsolicit_count = IGMP_Unsolicited_Report_Count;
 #endif