drivers/net: fix mislocated headers in cxgb4/l2t.c

For some reason three #include <linux/...> are buried way
down in the file.  Since the inclusion of module.h is one
of them, the inclusion comes after use of EXPORT_SYMBOL
which will cause warnings about implicit declarations.
Relocate all the headers to the top.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/net/ethernet/chelsio/cxgb4/l2t.c

@@ -37,6 +37,9 @@
 #include <linux/if.h>
 #include <linux/if_vlan.h>
 #include <linux/jhash.h>
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
 #include <net/neighbour.h>
 #include "cxgb4.h"
 #include "l2t.h"
@@ -503,10 +506,6 @@ struct l2t_data *t4_init_l2t(void)
 	return d;
 }
 
-#include <linux/module.h>
-#include <linux/debugfs.h>
-#include <linux/seq_file.h>
-
 static inline void *l2t_get_idx(struct seq_file *seq, loff_t pos)
 {
 	struct l2t_entry *l2tab = seq->private;