spi: ppc4xx: Fix fallout from rename in struct spi_bitbang

I failed to adapt this driver because it's not enabled in a powerpc
allmodconfig build and also wasn't hit by my grep expertise. Fix
accordingly.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402100815.XQXw9XCF-lkp@intel.com/
Fixes: 22592331 ("spi: bitbang: Follow renaming of SPI "master" to "controller"")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20240210164006.208149-7-u.kleine-koenig@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-ppc4xx.c

@@ -364,22 +364,22 @@ static int spi_ppc4xx_of_probe(struct platform_device *op)
 
 	/* Setup the state for the bitbang driver */
 	bbp = &hw->bitbang;
-	bbp->master = hw->host;
+	bbp->ctlr = hw->host;
 	bbp->setup_transfer = spi_ppc4xx_setupxfer;
 	bbp->txrx_bufs = spi_ppc4xx_txrx;
 	bbp->use_dma = 0;
-	bbp->master->setup = spi_ppc4xx_setup;
-	bbp->master->cleanup = spi_ppc4xx_cleanup;
-	bbp->master->bits_per_word_mask = SPI_BPW_MASK(8);
-	bbp->master->use_gpio_descriptors = true;
+	bbp->ctlr->setup = spi_ppc4xx_setup;
+	bbp->ctlr->cleanup = spi_ppc4xx_cleanup;
+	bbp->ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
+	bbp->ctlr->use_gpio_descriptors = true;
 	/*
 	 * The SPI core will count the number of GPIO descriptors to figure
 	 * out the number of chip selects available on the platform.
 	 */
-	bbp->master->num_chipselect = 0;
+	bbp->ctlr->num_chipselect = 0;
 
 	/* the spi->mode bits understood by this driver: */
-	bbp->master->mode_bits =
+	bbp->ctlr->mode_bits =
 		SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST;
 
 	/* Get the clock for the OPB */