x86/msi: Provide new iommu irqdomain interface

x86/msi: Provide new iommu irqdomain interface

Provide a new interface for creating the iommu remapping domains, so that
the caller can supply a name and a id in order to create named irqdomains.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: iommu@lists.linux-foundation.org
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235443.986661206@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>