drivers: soc: atmel: Avoid calling at91_soc_init on non AT91 SoCs

Since at91_soc_init is called unconditionally from atmel_soc_device_init,
we get the following warning on all non AT91 SoCs:
	" AT91: Could not find identification node"

Fix the same by filtering with allowed AT91 SoC list.

Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201211135846.1334322-1-sudeep.holla@arm.com

drivers/soc/atmel/soc.c

@@ -271,8 +271,20 @@ struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
 	return soc_dev;
 }
 
+static const struct of_device_id at91_soc_allowed_list[] __initconst = {
+	{ .compatible = "atmel,at91rm9200", },
+	{ .compatible = "atmel,at91sam9", },
+	{ .compatible = "atmel,sama5", },
+	{ .compatible = "atmel,samv7", }
+};
+
 static int __init atmel_soc_device_init(void)
 {
+	struct device_node *np = of_find_node_by_path("/");
+
+	if (!of_match_node(at91_soc_allowed_list, np))
+		return 0;
+
 	at91_soc_init(socs);
 
 	return 0;