[IPV4]: trivial igmp annotations

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/igmp.h b/include/linux/igmp.h
index 7514cce..03f43e2 100644
--- a/include/linux/igmp.h
+++ b/include/linux/igmp.h
@@ -140,7 +140,7 @@
 };
 
 #define IP_SFLSIZE(count)	(sizeof(struct ip_sf_socklist) + \
-	(count) * sizeof(__u32))
+	(count) * sizeof(__be32))
 
 #define IP_SFBLOCK	10	/* allocate this many at once */