net: hdlc_x25: Return meaningful error code in x25_open

It's not meaningful to pass on LAPB error codes to HDLC code or other
parts of the system, because they will not understand the error codes.

Instead, use system-wide recognizable error codes.

Fixes: f362e5f ("wan/hdlc_x25: make lapb params configurable")
Fixes: 1da177e ("Linux-2.6.12-rc2")
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Acked-by: Martin Schiller <ms@dev.tdt.de>
Link: https://lore.kernel.org/r/20210203071541.86138-1-xie.he.0141@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Xie He

drivers/net/wan/hdlc_x25.c

@@ -169,11 +169,11 @@ static int x25_open(struct net_device *dev)
 
 	result = lapb_register(dev, &cb);
 	if (result != LAPB_OK)
-		return result;
+		return -ENOMEM;
 
 	result = lapb_getparms(dev, &params);
 	if (result != LAPB_OK)
-		return result;
+		return -EINVAL;
 
 	if (state(hdlc)->settings.dce)
 		params.mode = params.mode | LAPB_DCE;
@@ -188,7 +188,7 @@ static int x25_open(struct net_device *dev)
 
 	result = lapb_setparms(dev, &params);
 	if (result != LAPB_OK)
-		return result;
+		return -EINVAL;
 
 	return 0;
 }