iommu/fsl: Add additional iommu attributes required by the PAMU driver.

Added the following domain attributes for the FSL PAMU driver:
1. Added new iommu stash attribute, which allows setting of the
   LIODN specific stash id parameter through IOMMU API.
2. Added an attribute for enabling/disabling DMA to a particular
   memory window.
3. Added domain attribute to check for PAMUV1 specific constraints.

Signed-off-by: Varun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>