backlight: pwm_bl: Avoid open coded arithmetic in memory allocation

kmalloc_array()/kcalloc() should be used to avoid potential overflow when
a multiplication is needed to compute the size of the requested memory.

So turn a kzalloc()+explicit size computation into an equivalent kcalloc().

Signed-off-by: Christophe JAILLET <[e-mail]>
Acked-by: Uwe Kleine-König <[e-mail]>
Reviewed-by: Daniel Thompson <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>
Link: https://lore.kernel.org/r/bd3d74acfa[e-mail]

drivers/video/backlight/pwm_bl.c

···
 
 	/* read brightness levels from DT property */
 	if (num_levels > 0) {
-		size_t size = sizeof(*data->levels) * num_levels;
-
-		data->levels = devm_kzalloc(dev, size, GFP_KERNEL);
+		data->levels = devm_kcalloc(dev, num_levels,
+					    sizeof(*data->levels), GFP_KERNEL);
 		if (!data->levels)
 			return -ENOMEM;
 
···
 			 * Create a new table of brightness levels with all the
 			 * interpolated steps.
 			 */
-			size = sizeof(*table) * num_levels;
-			table = devm_kzalloc(dev, size, GFP_KERNEL);
+			table = devm_kcalloc(dev, num_levels, sizeof(*table),
+					     GFP_KERNEL);
 			if (!table)
 				return -ENOMEM;
 			/*