iommu, irq: alloc irq_desc for dmar_msi with local node

Also fix the return value checking problem.

create_irq() will return -1 when fail to allocate.
create_irq_nr() will return 0 when fail to allocate.

here only check !irq, so need to change it to create_irq_nr.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

1 file changed