powerpc/pasemi: Fix coherent_dma_mask for dma engine

Commit 817820b0 ("powerpc/iommu: Support "hybrid" iommu/direct DMA
ops for coherent_mask < dma_mask) adds a check of coherent_dma_mask for
dma allocations.

Unfortunately current PASemi code does not set this value for the DMA
engine, which ends up with the default value of 0xffffffff, the result
is on a PASemi system with >2Gb ram and iommu enabled the the onboard
ethernet stops working due to an inability to allocate memory. Add an
initialisation to pci_dma_dev_setup_pasemi().
Signed-off-by: Darren Stevens <darren@stevens-zone.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/pasemi/iommu.c

@@ -187,6 +187,11 @@ static void pci_dma_dev_setup_pasemi(struct pci_dev *dev)
 	if (dev->vendor == 0x1959 && dev->device == 0xa007 &&
 	    !firmware_has_feature(FW_FEATURE_LPAR)) {
 		dev->dev.archdata.dma_ops = &dma_direct_ops;
+		/*
+		 * Set the coherent DMA mask to prevent the iommu
+		 * being used unnecessarily
+		 */
+		dev->dev.coherent_dma_mask = DMA_BIT_MASK(44);
 		return;
 	}
 #endif