ipmi:ssif: Check dev before setting drvdata

dev can be NULL.
Reported-by: Austin Christ <austinwc@codeaurora.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/ipmi_ssif.c

@@ -1777,6 +1777,7 @@ static int new_ssif_client(int addr, char *adapter_name,
 	addr_info->addr_src = addr_src;
 	addr_info->dev = dev;
 
+	if (dev)
 		dev_set_drvdata(dev, addr_info);
 
 	list_add_tail(&addr_info->link, &ssif_infos);