iommu/fsl_pamu: remove fsl_pamu_get_domain_attr

None of the values returned by this function are ever queried.  Also
remove the DOMAIN_ATTR_FSL_PAMUV1 enum value that is not otherwise used.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Li Yang <leoyang.li@nxp.com>
Link: https://lore.kernel.org/r/20210401155256.298656-3-hch@lst.de


Signed-off-by: Joerg Roedel <jroedel@suse.de>