spi: stm32: use explicit CPOL and CPHA mode bits

Driver supports SPI mode 0 to 3 not only the mode 3.
Use SPI_CPOL and SPI_CPHA indicates that these bits
can be changed to obtain modes 0 - 3.
Signed-off-by: Cezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-stm32.c

@@ -1142,7 +1142,7 @@ static int stm32_spi_probe(struct platform_device *pdev)
 	master->dev.of_node = pdev->dev.of_node;
 	master->auto_runtime_pm = true;
 	master->bus_num = pdev->id;
-	master->mode_bits = SPI_MODE_3 | SPI_CS_HIGH | SPI_LSB_FIRST |
+	master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH | SPI_LSB_FIRST |
 			    SPI_3WIRE | SPI_LOOP;
 	master->bits_per_word_mask = stm32_spi_get_bpw_mask(spi);
 	master->max_speed_hz = spi->clk_rate / SPI_MBR_DIV_MIN;