net: fix multiple definitions of setup_w6692

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Karsten Keil <keil@b1-systems.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/isdn/hardware/mISDN/w6692.c

@@ -1234,7 +1234,7 @@ w6692_dctrl(struct mISDNchannel *ch, u32 cmd, void *arg)
 	return err;
 }
 
-int
+static int
 setup_w6692(struct w6692_hw *card)
 {
 	u32	val;