net: dsa: add includes for ethtool and phy_fixed definitions

net/dsa/slave.c uses functions and structures declared in phy_fixed.h
but does not explicitely include it, while dsa.h needs structure
declarations for 'struct ethtool_wolinfo' and 'struct ethtool_eee', fix
those by including the correct header files.

Fixes: ec9436ba ("net: dsa: allow drivers to do link adjustment")
Fixes: ce31b31c ("net: dsa: allow updating fixed PHY link information")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/dsa.h

@@ -18,6 +18,7 @@
 #include <linux/of.h>
 #include <linux/phy.h>
 #include <linux/phy_fixed.h>
+#include <linux/ethtool.h>
 
 enum dsa_tag_protocol {
 	DSA_TAG_PROTO_NONE = 0,

net/dsa/slave.c

@@ -11,6 +11,7 @@
 #include <linux/list.h>
 #include <linux/etherdevice.h>
 #include <linux/phy.h>
+#include <linux/phy_fixed.h>
 #include <linux/of_net.h>
 #include <linux/of_mdio.h>
 #include "dsa_priv.h"