net: caif: Remove unused declaration cfsrvl_ctrlcmd()

Commit 43e36921 ("caif: Move refcount from service layer to sock and dev.")
declared but never implemented this.
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230809134943.37844-1-yuehaibing@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/caif/cfsrvl.h

@@ -33,9 +33,6 @@ struct cflayer *cfrfml_create(u8 linkid, struct dev_info *dev_info,
 				int mtu_size);
 struct cflayer *cfdbgl_create(u8 linkid, struct dev_info *dev_info);
 
-void cfsrvl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
-		     int phyid);
-
 bool cfsrvl_phyid_match(struct cflayer *layer, int phyid);
 
 void cfsrvl_init(struct cfsrvl *service,