NVIDIA Tegra MIPI pad calibration controller

Required properties:
- compatible: "nvidia,tegra<chip>-mipi"
- reg: Physical base address and length of the controller's registers.
- clocks: Must contain an entry for each entry in clock-names.
  See ../clocks/clock-bindings.txt for details.
- clock-names: Must include the following entries:
  - mipi-cal
- #nvidia,mipi-calibrate-cells: Should be 1. The cell is a bitmask of the pads
  that need to be calibrated for a given device.

User nodes need to contain an nvidia,mipi-calibrate property that has a
phandle to refer to the calibration controller node and a bitmask of the pads
that need to be calibrated.

Example:

	mipi: mipi@700e3000 {
		compatible = "nvidia,tegra114-mipi";
		reg = <0x700e3000 0x100>;
		clocks = <&tegra_car TEGRA114_CLK_MIPI_CAL>;
		clock-names = "mipi-cal";
		#nvidia,mipi-calibrate-cells = <1>;
	};

	...

	host1x@50000000 {
		...

		dsi@54300000 {
			...

			nvidia,mipi-calibrate = <&mipi 0x060>;

			...
		};

		...
	};