net: add missing includes of linux/splice.h

Number of files depend on linux/splice.h getting included
by linux/skbuff.h which soon will no longer be the case.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 036532c..1c0fe9b 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -27,6 +27,7 @@
 #include <linux/if_vlan.h>
 #include <linux/rcupdate_wait.h>
 #include <linux/ctype.h>
+#include <linux/splice.h>
 
 #include <net/sock.h>
 #include <net/tcp.h>