IRQ remapping is only supported when all IOMMUs in the
system support it. So check if all IOMMUs in the system
support IRQ remapping before doing the allocations.

[Jiang]
1) Rebased to v3.19.
2) Remove redundant check of ecap_ir_support(iommu->ecap) in function
   intel_enable_irq_remapping().
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Tested-by: NJoerg Roedel <joro@8bytes.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/1420615903-28253-10-git-send-email-jiang.liu@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>