spi: imx: add function to check for IMX51 family controller

Similar to other controller type checks add check function for
IMX51. It includes IMX53 and IMX6.

Signed-off-by: Anton Bondarenko <anton.bondarenko.sama@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index beba40b..410522f 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -122,9 +122,14 @@
 	return d->devtype_data->devtype == IMX35_CSPI;
 }
 
+static inline int is_imx51_ecspi(struct spi_imx_data *d)
+{
+	return d->devtype_data->devtype == IMX51_ECSPI;
+}
+
 static inline unsigned spi_imx_get_fifosize(struct spi_imx_data *d)
 {
-	return (d->devtype_data->devtype == IMX51_ECSPI) ? 64 : 8;
+	return is_imx51_ecspi(d) ? 64 : 8;
 }
 
 #define MXC_SPI_BUF_RX(type)						\
@@ -1210,8 +1215,8 @@
 	 * Only validated on i.mx6 now, can remove the constrain if validated on
 	 * other chips.
 	 */
-	if (spi_imx->devtype_data == &imx51_ecspi_devtype_data
-	    && spi_imx_sdma_init(&pdev->dev, spi_imx, master, res))
+	if (is_imx51_ecspi(spi_imx) &&
+	    spi_imx_sdma_init(&pdev->dev, spi_imx, master, res))
 		dev_err(&pdev->dev, "dma setup error,use pio instead\n");
 
 	spi_imx->devtype_data->reset(spi_imx);