serial: Add driver for LPC32xx High Speed UARTs

This patch adds a driver for the 3 High Speed UARTs of the LPC32xx SoC that
support up to 921600bps. These UARTs are different from the 4 "Standard" UARTs
of the LPC32xx.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/tty/serial/nxp-lpc32xx-hsuart.txt

@@ -0,0 +1,14 @@
+* NXP LPC32xx SoC High Speed UART
+
+Required properties:
+- compatible: Should be "nxp,lpc3220-hsuart"
+- reg: Should contain registers location and length
+- interrupts: Should contain interrupt
+
+Example:
+
+	uart1: serial@40014000 {
+		compatible = "nxp,lpc3220-hsuart";
+		reg = <0x40014000 0x1000>;
+		interrupts = <26 0>;
+	};