gpib: tnt4882: Unify *allocate_private return value

Return -ENOMEM instead of -1 in tnt4882_allocate_private in case of
memory allocation failure.

Signed-off-by: Dominik Karol Piątkowski <dominik.karol.piatkowski@protonmail.com>
Link: https://patch.msgid.link/20260116174647.317256-27-dominik.karol.piatkowski@protonmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Kotbenek

drivers/gpib/tnt4882/tnt4882_gpib.c

@@ -845,7 +845,7 @@ static int tnt4882_allocate_private(struct gpib_board *board)
 
 	board->private_data = kzalloc(sizeof(struct tnt4882_priv), GFP_KERNEL);
 	if (!board->private_data)
-		return -1;
+		return -ENOMEM;
 	tnt_priv = board->private_data;
 	init_nec7210_private(&tnt_priv->nec7210_priv);
 	return 0;