serial: 8250_dw: Add compatible string for Renesas RZ/N1 UART

The Renesas RZ/N1 UART is based on the Synopsys DW UART, but has additional
registers for DMA. This patch does not address the changes required for DMA
support, it simply adds the compatible string.
Signed-off-by: NPhil Edworthy <phil.edworthy@renesas.com>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_dw.c

@@ -747,6 +747,7 @@ static const struct of_device_id dw8250_of_match[] = {
 	{ .compatible = "snps,dw-apb-uart" },
 	{ .compatible = "cavium,octeon-3860-uart" },
 	{ .compatible = "marvell,armada-38x-uart" },
+	{ .compatible = "renesas,rzn1-uart" },
 	{ /* Sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, dw8250_of_match);