gpu: ipu-v3: image-convert: allow three rows or columns

If width or height are in the [2049, 3072] range, allow to
use just three tiles in this dimension, instead of four.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Steve Longerbeam <slongerbeam@gmail.com>
Tested-by: Steve Longerbeam <slongerbeam@gmail.com>

drivers/gpu/ipu-v3/ipu-image-convert.c

@@ -379,12 +379,7 @@ static int alloc_dma_buf(struct ipu_image_convert_priv *priv,
 
 static inline int num_stripes(int dim)
 {
-	if (dim <= 1024)
-		return 1;
-	else if (dim <= 2048)
-		return 2;
-	else
-		return 4;
+	return (dim - 1) / 1024 + 1;
 }
 
 /*