s390/pci: Fix dev.dma_range_map missing sentinel element

s390/pci: Fix dev.dma_range_map missing sentinel element

The fixed commit sets up dev.dma_range_map but missed that this is
supposed to be an array of struct bus_dma_region with a sentinel element
with the size field set to 0 at the end. This would lead to overruns in
e.g. dma_range_map_min(). It could also result in wrong translations
instead of DMA_MAPPING_ERROR in translate_phys_to_dma() if the paddr
were to not fit in the aperture. Fix this by using the
dma_direct_set_offset() helper which creates a sentinel for us.

Fixes: d236843a6964 ("s390/pci: store DMA offset in bus_dma_region")
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20250312-fix_dma_map_alloc-v2-1-530108d9de21@linux.ibm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>