net: hns: Remove unused function declaration mac_adjust_link()

Commit 511e6bc0 ("net: add Hisilicon Network Subsystem DSAF support")
declared but never implemented this, remove it.
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Hao Lan <lanhao@huawei.com>
Link: https://lore.kernel.org/r/20230804130048.39808-1-yuehaibing@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.h

@@ -422,7 +422,6 @@ void *hns_xgmac_config(struct hns_mac_cb *mac_cb,
 		       struct mac_params *mac_param);
 
 int hns_mac_init(struct dsaf_device *dsaf_dev);
-void mac_adjust_link(struct net_device *net_dev);
 bool hns_mac_need_adjust_link(struct hns_mac_cb *mac_cb, int speed, int duplex);
 void hns_mac_get_link_status(struct hns_mac_cb *mac_cb,	u32 *link_status);
 int hns_mac_change_vf_addr(struct hns_mac_cb *mac_cb, u32 vmid,