net: ethernet: remove fs_mii_disconnect and fs_mii_connect declarations

fs_mii_disconnect and fs_mii_connect have been removed since
commit 5b4b8454 ("[PATCH] FS_ENET: use PAL for mii management"),
so remove them.
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20220909062959.1144493-1-cuigaosheng1@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c

@@ -883,9 +883,6 @@ static const struct ethtool_ops fs_ethtool_ops = {
 	.set_tunable = fs_set_tunable,
 };
 
-extern int fs_mii_connect(struct net_device *dev);
-extern void fs_mii_disconnect(struct net_device *dev);
-
 /**************************************************************************************/
 
 #ifdef CONFIG_FS_ENET_HAS_FEC