spi: fsl: Use kmalloc_array() in of_fsl_spi_get_chipselects()

A multiplication for the size determination of a memory allocation
indicated that an array data structure should be processed.
Thus use the corresponding function "kmalloc_array".

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-spi.c

@@ -727,7 +727,8 @@ static int of_fsl_spi_get_chipselects(struct device *dev)
 		return 0;
 	}
 
-	pinfo->gpios = kmalloc(ngpios * sizeof(*pinfo->gpios), GFP_KERNEL);
+	pinfo->gpios = kmalloc_array(ngpios, sizeof(*pinfo->gpios),
+				     GFP_KERNEL);
 	if (!pinfo->gpios)
 		return -ENOMEM;
 	memset(pinfo->gpios, -1, ngpios * sizeof(*pinfo->gpios));