s390/ism: Set DMA coherent mask

s390/ism: Set DMA coherent mask

A future change will convert the DMA API implementation from the
architecture specific arch/s390/pci/pci_dma.c to using the common code
drivers/iommu/dma-iommu.c which the utilizes the same IOMMU hardware
through the s390-iommu driver. Unlike the s390 specific DMA API this
requires devices to correctly set the coherent mask to be allowed to use
IOVAs >2^32 in dma_alloc_coherent(). This was however not done for ISM
devices. ISM requires such addresses since currently the DMA aperture
for PCI devices starts at 2^32 and all calls to dma_alloc_coherent()
would thus fail.

Link: https://lore.kernel.org/all/20230310-dma_iommu-v9-1-65bb8edd2beb@linux.ibm.com/
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20230524075411.3734141-1-schnelle@linux.ibm.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>