net/hsr: Move slave init to hsr_slave.c.

Also try to prevent some possible slave dereference race conditions. This is
finalized in the next patch, which abandons the slave array in favour of
a list_head list and list RCU.

Signed-off-by: Arvid Brodin <arvid.brodin@alten.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/hsr/hsr_slave.h b/net/hsr/hsr_slave.h
index ae90c8d..03c15fd 100644
--- a/net/hsr/hsr_slave.h
+++ b/net/hsr/hsr_slave.h
@@ -14,7 +14,10 @@
 
 #include <linux/skbuff.h>
 #include <linux/netdevice.h>
+#include "hsr_main.h"
 
+int hsr_add_slave(struct hsr_priv *hsr, struct net_device *dev, int idx);
+void hsr_del_slave(struct hsr_priv *hsr, int idx);
 rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb);
 
 #endif /* __HSR_SLAVE_H */