dccp: Remove unused declaration dccp_feat_initialise_sysctls()

This is never used, so can remove it.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230726143239.9904-1-yuehaibing@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/dccp/feat.h

@@ -105,7 +105,6 @@ extern int	     sysctl_dccp_rx_ccid;
 extern int	     sysctl_dccp_tx_ccid;
 
 int dccp_feat_init(struct sock *sk);
-void dccp_feat_initialise_sysctls(void);
 int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
 			  u8 const *list, u8 len);
 int dccp_feat_parse_options(struct sock *, struct dccp_request_sock *,