DMA: ste_dma40: use a power of 2 check

dst_addr_width and src_addr_width should be a power of 2. Currently the
driver checks, that they both lie between 1 and 8 and that they are equal
to 1 or even. This however leaves an invalid value of 6 uncaught. Use an
explicit power of 2 check instead.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
[typo fix on changelog]
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/ste_dma40.c

@@ -14,6 +14,7 @@
 #include <linux/platform_device.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/log2.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
 #include <linux/err.h>
@@ -2796,8 +2797,8 @@ static int d40_set_runtime_config(struct dma_chan *chan,
 	    src_addr_width >  DMA_SLAVE_BUSWIDTH_8_BYTES   ||
 	    dst_addr_width <= DMA_SLAVE_BUSWIDTH_UNDEFINED ||
 	    dst_addr_width >  DMA_SLAVE_BUSWIDTH_8_BYTES   ||
-	    ((src_addr_width > 1) && (src_addr_width & 1)) ||
-	    ((dst_addr_width > 1) && (dst_addr_width & 1)))
+	    !is_power_of_2(src_addr_width) ||
+	    !is_power_of_2(dst_addr_width))
 		return -EINVAL;
 
 	cfg->src_info.data_width = src_addr_width;