net: xgene: Move shared header file into include/linux

This header file is currently included into the ethernet driver via a
relative path into the PHY subsystem. This is bad practice, and causes
issues for the upcoming move of the MDIO driver. Move the header file
into include/linux to clean this up.

v2:
Move header to include/linux/mdio

Reviewed-by: Florian Fainelli <[e-mail]>
Signed-off-by: Andrew Lunn <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/apm/xgene/xgene_enet_main.h

···
 #include <linux/of_platform.h>
 #include <linux/of_net.h>
 #include <linux/of_mdio.h>
+#include <linux/mdio/mdio-xgene.h>
 #include <linux/module.h>
 #include <net/ip.h>
 #include <linux/prefetch.h>
···
 #include "xgene_enet_hw.h"
 #include "xgene_enet_cle.h"
 #include "xgene_enet_ring2.h"
-#include "../../../phy/mdio-xgene.h"
 
 #define ETHER_MIN_PACKET	64
 #define ETHER_STD_PACKET	1518

drivers/net/phy/mdio-xgene.c

···
 #include <linux/efi.h>
 #include <linux/if_vlan.h>
 #include <linux/io.h>
+#include <linux/mdio/mdio-xgene.h>
 #include <linux/module.h>
 #include <linux/of_platform.h>
 #include <linux/of_net.h>
···
 #include <linux/prefetch.h>
 #include <linux/phy.h>
 #include <net/ip.h>
-#include "mdio-xgene.h"
 
 static bool xgene_mdio_status;