spi: fix parent-device reference leak

Fix parent-device reference leak due to SPI-core taking an unnecessary
reference to the parent when allocating the master structure, a
reference that was never released.

Note that driver core takes its own reference to the parent when the
master device is registered.

Fixes: 49dce689ad ("spi doesn't need class_device")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

drivers/spi/spi.c

@@ -1704,7 +1704,7 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
 	master->bus_num = -1;
 	master->num_chipselect = 1;
 	master->dev.class = &spi_master_class;
-	master->dev.parent = get_device(dev);
+	master->dev.parent = dev;
 	spi_master_set_devdata(master, &master[1]);
 
 	return master;