linux-wandboard

x86/amd-iommu: Improve handling of full command buffer

This patch improved the handling of commands when the IOMMU
command buffer is nearly full. In this case it issues an
completion wait command and waits until the IOMMU has
processed it before continuing queuing new commands.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>