mtd: sst25l: check for null consistently

The rest of the function assumes that "data" can be null.  I don't know
the code well enough to say whether it can actually be null, but there
is no harm in checking here.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/devices/sst25l.c

@@ -454,7 +454,7 @@ static int __init sst25l_probe(struct spi_device *spi)
 						  parts, nr_parts);
 		}
 
-	} else if (data->nr_parts) {
+	} else if (data && data->nr_parts) {
 		dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
 			 data->nr_parts, data->name);
 	}