If the port number is missing from the device-tree the device gets named
xs` instead of xsa.  This fixes the check for missing ids.
Tested on ml507 board.
Signed-off-by: Gernot Vormayr <gvormayr@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
        dev_dbg(&dev->dev, "ace_probe(%p)\n", dev);
 
        /* device id and bus width */
-       of_property_read_u32(dev->dev.of_node, "port-number", &id);
-       if (id < 0)
+       if (of_property_read_u32(dev->dev.of_node, "port-number", &id))
                id = 0;
        if (of_find_property(dev->dev.of_node, "8-bit", NULL))
                bus_width = ACE_BUS_WIDTH_8;