[janitor] update the sdlamain Multiprotocol WAN Link Driver to

        1) check the status of call to request_region 
        2) and return an error in case of problem.

Note that a call to check_region still remains in this driver (in subroutine check_s508_conflicts). 

I don't have this hardware so compilation checked only.

drivers/net/wan/sdlamain.c

@@ -604,7 +604,13 @@ static int setup (wan_device_t* wandev, wandev_conf_t* conf)
 
   	/* Reserve I/O region and schedule background task */
         if(card->hw.type != SDLA_S514 && !card->wandev.piggyback)
-                request_region(card->hw.port, card->hw.io_range, wandev->name);
+		if (!request_region(card->hw.port, card->hw.io_range, 
+				wandev->name)) {
+			printk(KERN_WARNING "port 0x%04x busy\n", card->hw.port);
+			release_hw(card);
+			wandev->state = WAN_UNCONFIGURED;
+			return -EBUSY;
+	  }
 
 	/* Only use the polling routine for the X25 protocol */