iommu/amd: Use AMD specific data structure for irq remapping

For compatibility reasons the irq remapping code for the AMD
IOMMU used the same per-irq data structure as the Intel
implementation. Now that support for the AMD specific data
structure is upstream we can use this one instead.

Reviewed-by: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>