fbdev: fsl-diu: get cpu node with of_get_cpu_node

"device_type" use is deprecated for FDT though it has continued to be used
for nodes like cpu nodes. Use of_get_cpu_node() instead which works using
node names by default. This will allow the eventually removal of cpu
device_type properties.
Acked-by: Timur Tabi <timur@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/video/fbdev/fsl-diu-fb.c

@@ -1925,7 +1925,7 @@ static int __init fsl_diu_init(void)
 	pr_info("Freescale Display Interface Unit (DIU) framebuffer driver\n");
 
 #ifdef CONFIG_NOT_COHERENT_CACHE
-	np = of_find_node_by_type(NULL, "cpu");
+	np = of_get_cpu_node(0, NULL);
 	if (!np) {
 		pr_err("fsl-diu-fb: can't find 'cpu' device node\n");
 		return -ENODEV;