net: qualcomm: rmnet: always expose a few functions

A recent change tidied up some conditional code, avoiding the use of
some #ifdefs.  Unfortunately, if CONFIG_IPV6 was not enabled, it
meant that two functions were referenced but never defined.

The easiest fix is to just define stubs for these functions if
CONFIG_IPV6 is not defined.  This will soon be simplified further
by some other development in the works...

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 75db5b07f8 ("net: qualcomm: rmnet: eliminate some ifdefs")
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c

@@ -153,6 +153,14 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
 	priv->stats.csum_ok++;
 	return 0;
 }
+#else
+static int
+rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
+			       struct rmnet_map_dl_csum_trailer *csum_trailer,
+			       struct rmnet_priv *priv)
+{
+	return 0;
+}
 #endif
 
 static void rmnet_map_complement_ipv4_txporthdr_csum_field(void *iphdr)
@@ -223,6 +231,13 @@ rmnet_map_ipv6_ul_csum_header(struct ipv6hdr *ipv6hdr,
 
 	rmnet_map_complement_ipv6_txporthdr_csum_field(ipv6hdr);
 }
+#else
+static void
+rmnet_map_ipv6_ul_csum_header(void *ip6hdr,
+			      struct rmnet_map_ul_csum_header *ul_header,
+			      struct sk_buff *skb)
+{
+}
 #endif
 
 static void rmnet_map_v5_checksum_uplink_packet(struct sk_buff *skb,