[NET]: Fix MAX_HEADER setting.

MAX_HEADER is either set to LL_MAX_HEADER or LL_MAX_HEADER + 48, and
this is controlled by a set of CONFIG_* ifdef tests.

It is trying to use LL_MAX_HEADER + 48 when any of the tunnels are
enabled which set hard_header_len like this:

dev->hard_header_len = LL_MAX_HEADER + sizeof(struct xxx);

The correct set of tunnel drivers which do this are:

ipip
ip_gre
ip6_tunnel
sit

so make the ifdef test match.

Noticed by Patrick McHardy and with help from Herbert Xu.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -93,8 +93,10 @@ struct netpoll_info;
 #endif
 #endif
 
-#if !defined(CONFIG_NET_IPIP) && \
-    !defined(CONFIG_IPV6) && !defined(CONFIG_IPV6_MODULE)
+#if !defined(CONFIG_NET_IPIP) && !defined(CONFIG_NET_IPIP_MODULE) && \
+    !defined(CONFIG_NET_IPGRE) &&  !defined(CONFIG_NET_IPGRE_MODULE) && \
+    !defined(CONFIG_IPV6_SIT) && !defined(CONFIG_IPV6_SIT_MODULE) && \
+    !defined(CONFIG_IPV6_TUNNEL) && !defined(CONFIG_IPV6_TUNNEL_MODULE)
 #define MAX_HEADER LL_MAX_HEADER
 #else
 #define MAX_HEADER (LL_MAX_HEADER + 48)