OMAP2+ IOMMU

Required properties:
- compatible : Should be one of,
		"ti,omap2-iommu" for OMAP2/OMAP3 IOMMU instances
		"ti,omap4-iommu" for OMAP4/OMAP5 IOMMU instances
		"ti,dra7-iommu" for DRA7xx IOMMU instances
- ti,hwmods  : Name of the hwmod associated with the IOMMU instance
- reg        : Address space for the configuration registers
- interrupts : Interrupt specifier for the IOMMU instance
- #iommu-cells : Should be 0. OMAP IOMMUs are all "single-master" devices,
                 and needs no additional data in the pargs specifier. Please
                 also refer to the generic bindings document for more info
                 on this property,
                     Documentation/devicetree/bindings/iommu/iommu.txt

Optional properties:
- ti,#tlb-entries : Number of entries in the translation look-aside buffer.
                    Should be either 8 or 32 (default: 32)
- ti,iommu-bus-err-back : Indicates the IOMMU instance supports throwing
		          back a bus error response on MMU faults.

Example:
	/* OMAP3 ISP MMU */
	mmu_isp: mmu@480bd400 {
		#iommu-cells = <0>;
		compatible = "ti,omap2-iommu";
		reg = <0x480bd400 0x80>;
		interrupts = <24>;
		ti,hwmods = "mmu_isp";
		ti,#tlb-entries = <8>;
	};
