gdsys Gazerbeam board driver

This driver provides capabilities to access the gdsys Gazerbeam board's device
information. Furthermore, phandles to some internal devices are provided for
the board files.

Required properties:
- compatible:  should be "gdsys,board_gazerbeam"
- csb:         phandle to the board's coherent system bus (CSB) device node
- rxaui[0-3]:  phandles to the rxaui control device nodes
- fpga[0-1]:   phandles to the board's gdsys FPGA device nodes
- ioep[0-1]:   phandles to the board's IO endpoint device nodes
- ver-gpios:   GPIO list to read the hardware version from
- var-gpios:   GPIO list to read the hardware variant information from
- reset-gpios: GPIO list for the board's reset GPIOs

Example:


board {
	compatible = "gdsys,board_gazerbeam";
	csb = <&board_soc>;
	serdes = <&SERDES>;
	rxaui0 = <&RXAUI0>;
	rxaui1 = <&RXAUI1>;
	rxaui2 = <&RXAUI2>;
	rxaui3 = <&RXAUI3>;
	fpga0 = <&FPGA0>;
	fpga1 = <&FPGA1>;
	ioep0 = <&IOEP0>;
	ioep1 = <&IOEP1>;

	ver-gpios = <&PPCPCA 12 0
		     &PPCPCA 13 0
		     &PPCPCA 14 0
		     &PPCPCA 15 0>;

	/* MC2/SC-Board */
	var-gpios-mc2 = <&GPIO_VB0 0 0    /* VAR-MC_SC */
			 &GPIO_VB0 11 0>; /* VAR-CON */
	/* MC4-Board */
	var-gpios-mc4 = <&GPIO_VB1 0 0    /* VAR-MC_SC */
			 &GPIO_VB1 11 0>; /* VAR-CON */

	reset-gpios = <&gpio0 1 0 &gpio0 2 1>;
};