iommu: Fix compile error with !IOMMU_API

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 93617e7..0f318fd54 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -181,7 +181,7 @@
 {
 }
 
-static inline int iommu_device_group(struct device *dev, unsigned int *groupid);
+static inline int iommu_device_group(struct device *dev, unsigned int *groupid)
 {
 	return -ENODEV;
 }