powerpc/eeh: Export eeh_iommu_group_to_pe()

The function is used by VFIO driver, which might be built as a
dynamic module. So it should be exported.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/eeh.c

@@ -1254,6 +1254,7 @@ struct eeh_pe *eeh_iommu_group_to_pe(struct iommu_group *group)
 
 	return edev->pe;
 }
+EXPORT_SYMBOL_GPL(eeh_iommu_group_to_pe);
 
 #endif /* CONFIG_IOMMU_API */