mtd: dataflash: Follow renaming of SPI "master" to "controller"

In commit 8caab75f ("spi: Generalize SPI "master" to "controller"")
some functions and struct members were renamed. To not break all drivers
compatibility macros were provided.

To be able to remove these compatibility macros push the renaming into
this driver.
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/38bf50b391c117621e406fa8cd00c4daef78615c.1707324794.git.u.kleine-koenig@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/mtd/devices/mtd_dataflash.c

@@ -638,7 +638,7 @@ static int add_dataflash_otp(struct spi_device *spi, char *name, int nr_pages,
 
 	/* name must be usable with cmdlinepart */
 	sprintf(priv->name, "spi%d.%d-%s",
-			spi->master->bus_num, spi_get_chipselect(spi, 0),
+			spi->controller->bus_num, spi_get_chipselect(spi, 0),
 			name);
 
 	device = &priv->mtd;