hwrng: atmel - add DT support

Add DT support.

Make the driver depend on CONFIG_OF as at91sam9g45 was the only SoC making
use of the TRNG block and this SoC is now fully migrated to DT.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Peter Korsgaard <peter@korsgaard.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/char/hw_random/Kconfig

@@ -64,7 +64,7 @@ config HW_RANDOM_AMD
 
 config HW_RANDOM_ATMEL
 	tristate "Atmel Random Number Generator support"
-	depends on ARCH_AT91 && HAVE_CLK
+	depends on ARCH_AT91 && HAVE_CLK && OF
 	default HW_RANDOM
 	---help---
 	  This driver provides kernel-side support for the Random Number

drivers/char/hw_random/atmel-rng.c

@@ -123,6 +123,12 @@ static const struct dev_pm_ops atmel_trng_pm_ops = {
 };
 #endif /* CONFIG_PM */
 
+static const struct of_device_id atmel_trng_dt_ids[] = {
+	{ .compatible = "atmel,at91sam9g45-trng" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, atmel_trng_dt_ids);
+
 static struct platform_driver atmel_trng_driver = {
 	.probe		= atmel_trng_probe,
 	.remove		= atmel_trng_remove,
@@ -132,6 +138,7 @@ static struct platform_driver atmel_trng_driver = {
 #ifdef CONFIG_PM
 		.pm	= &atmel_trng_pm_ops,
 #endif /* CONFIG_PM */
+		.of_match_table = atmel_trng_dt_ids,
 	},
 };