net/hsr: Remove unused function declarations

commit f421436a591d ("net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)")
introducted these but never implemented.

Signed-off-by: Yue Haibing <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/hsr/hsr_netlink.h

···
 void hsr_nl_ringerror(struct hsr_priv *hsr, unsigned char addr[ETH_ALEN],
 		      struct hsr_port *port);
 void hsr_nl_nodedown(struct hsr_priv *hsr, unsigned char addr[ETH_ALEN]);
-void hsr_nl_framedrop(int dropcount, int dev_idx);
-void hsr_nl_linkdown(int dev_idx);
 
 #endif /* __HSR_NETLINK_H */