serial: tegra: add serial driver

NVIDIA Tegra20/Tegra30 high speed (DMA based) UART controller driver.

Required properties:

- compatible : should be "nvidia,tegra30-hsuart", "nvidia,tegra20-hsuart".

- reg: Should contain UART controller registers location and length.

- interrupts: Should contain UART controller interrupts.

- nvidia,dma-request-selector : The Tegra DMA controller's phandle and

  request selector for this UART controller.

Optional properties:

- nvidia,enable-modem-interrupt: Enable modem interrupts. Should be enable

		only if all 8 lines of UART controller are pinmuxed.

Example:

serial@70006000 {

	compatible = "nvidia,tegra30-hsuart", "nvidia,tegra20-hsuart";

	reg = <0x70006000 0x40>;

	reg-shift = <2>;

	interrupts = <0 36 0x04>;

	nvidia,dma-request-selector = <&apbdma 8>;

	nvidia,enable-modem-interrupt;

	status = "disabled";

};

          your boot loader about how to pass options to the kernel at

          boot time.)

config SERIAL_TEGRA

	tristate "NVIDIA Tegra20/30 SoC serial controller"

	depends on ARCH_TEGRA && TEGRA20_APB_DMA

	select SERIAL_CORE

	help

	  Support for the on-chip UARTs on the NVIDIA Tegra series SOCs

	  providing /dev/ttyHS0, 1, 2, 3 and 4 (note, some machines may not

	  provide all of these ports, depending on how the serial port

	  are enabled). This driver uses the APB DMA to achieve higher baudrate

	  and better performance.

config SERIAL_MAX3100

	tristate "MAX3100 support"

	depends on SPI

obj-$(CONFIG_SERIAL_LANTIQ)	+= lantiq.o

obj-$(CONFIG_SERIAL_XILINX_PS_UART) += xilinx_uartps.o

obj-$(CONFIG_SERIAL_SIRFSOC) += sirfsoc_uart.o

obj-$(CONFIG_SERIAL_TEGRA) += serial-tegra.o

obj-$(CONFIG_SERIAL_AR933X)   += ar933x_uart.o

obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o

obj-$(CONFIG_SERIAL_ARC)	+= arc_uart.o