VT-d: use DMA_TLB_IVA_ADDR()

VT-d: use DMA_TLB_IVA_ADDR()

Let's use the macro in the one place it's supposed to be used, and in
favor of then unnecessary manipulations of the address in
iommu_flush_iotlb_psi(): All leaf functions then already deal correctly
with the supplied address.

There also has never been a need to require (i.e. assert for) the
passing in of 4k-aligned addresses - it'll always be the order-sized
range containing the address which gets flushed.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>