iommu-fixes-v4.11-rc3

A few fixes piled up:

	* Fix a NULL-ptr dereference that happens in VT-d on some
	  platforms

	* A fix for ARM MSI region reporting, so that a sane interface
	  makes it to a released kernel

	* Fixes for leaf-checking in ARM io-page-table code

	* Two fixes for IO/TLB flushing code on ARM Exynos platforms