spi: dw: Replace spi->chip_select references with function calls

New set/get APIs for accessing spi->chip_select were introduced by
'commit 9e264f3 ("spi: Replace all spi->chip_select and spi->cs_gpiod
references with function call")', but the 'commit 2c86060 ("spi: dw:
Add support for AMD Pensando Elba SoC")' uses the old interface by directly
accessing spi->chip_select. So, replace all spi->chip_select references
in the driver with new get/set APIs.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com
Acked-by: Serge Semin <fancer.lancer@gmail.com
Link: https://lore.kernel.org/r/20230515130343.63770-1-amit.kumar-mahapatra@amd.com
Signed-off-by: Mark Brown <broonie@kernel.org

drivers/spi/spi-dw-mmio.c

@@ -264,17 +264,17 @@ static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
 	struct regmap *syscon = dwsmmio->priv;
 	u8 cs;
 
-	cs = spi->chip_select;
+	cs = spi_get_chipselect(spi, 0);
 	if (cs < 2)
-		dw_spi_elba_override_cs(syscon, spi->chip_select, enable);
+		dw_spi_elba_override_cs(syscon, spi_get_chipselect(spi, 0), enable);
 
 	/*
 	 * The DW SPI controller needs a native CS bit selected to start
 	 * the serial engine.
 	 */
-	spi->chip_select = 0;
+	spi_set_chipselect(spi, 0, 0);
 	dw_spi_set_cs(spi, enable);
-	spi->chip_select = cs;
+	spi_get_chipselect(spi, cs);
 }
 
 static int dw_spi_elba_init(struct platform_device *pdev,