net: dsa: remove unused headers

Reduce a number of included headers to a necessary minimum.
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/dsa.c

@@ -7,19 +7,10 @@
 
 #include <linux/device.h>
 #include <linux/list.h>
-#include <linux/platform_device.h>
-#include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/notifier.h>
-#include <linux/of.h>
-#include <linux/of_mdio.h>
-#include <linux/of_platform.h>
-#include <linux/of_net.h>
 #include <linux/netdevice.h>
 #include <linux/sysfs.h>
-#include <linux/phy_fixed.h>
 #include <linux/ptp_classify.h>
-#include <linux/etherdevice.h>
 
 #include "dsa_priv.h"