net: dsa: hellcreek: Use the bitmap API to allocate bitmaps

Use devm_bitmap_zalloc() instead of hand-writing them.

It is less verbose and it improves the semantic.

Signed-off-by: Christophe JAILLET <[e-mail]>
Acked-by: Kurt Kanzenbach <[e-mail]>
Link: https://lore.kernel.org/r/8306e2ae69[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/dsa/hirschmann/hellcreek.c

···
 		if (!port->counter_values)
 			return -ENOMEM;
 
-		port->vlan_dev_bitmap =
-			devm_kcalloc(dev,
-				     BITS_TO_LONGS(VLAN_N_VID),
-				     sizeof(unsigned long),
-				     GFP_KERNEL);
+		port->vlan_dev_bitmap = devm_bitmap_zalloc(dev, VLAN_N_VID,
+							   GFP_KERNEL);
 		if (!port->vlan_dev_bitmap)
 			return -ENOMEM;