spi/spi-fsl-spi: reference correct pdata in fsl_spi_cs_control

Commit 178db7d3, "spi: Fix device unregistration when unregistering
the bus master", changed spi device initialization of dev.parent pointer
to be the master's device pointer instead of his parent.

This introduced a bug in spi-fsl-spi, since its usage of spi device
pointer was not updated accordingly. This was later fixed by commit
5039a869, "spi/mpc83xx: fix NULL pdata dereference bug", but it missed
another spot on fsl_spi_cs_control function where we also need to update
usage of spi device pointer. This change address that.

Cc: stable@vger.kernel.org
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Acked-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/spi/spi-fsl-spi.c

@@ -933,7 +933,7 @@ static struct spi_master * __devinit fsl_spi_probe(struct device *dev,
 
 static void fsl_spi_cs_control(struct spi_device *spi, bool on)
 {
-	struct device *dev = spi->dev.parent;
+	struct device *dev = spi->dev.parent->parent;
 	struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(dev->platform_data);
 	u16 cs = spi->chip_select;
 	int gpio = pinfo->gpios[cs];