spi: davinci: fix a NULL pointer dereference

BugLink: https://bugs.launchpad.net/bugs/1792419

commit 563a53f3 upstream.

On non-OF systems spi->controlled_data may be NULL. This causes a NULL
pointer derefence on dm365-evm.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/spi/spi-davinci.c

@@ -220,7 +220,7 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value)
 	pdata = &dspi->pdata;
 
 	/* program delay transfers if tx_delay is non zero */
-	if (spicfg->wdelay)
+	if (spicfg && spicfg->wdelay)
 		spidat1 |= SPIDAT1_WDEL;
 
 	/*