iommu: Fix wrong freeing of iommu_device->dev

The struct iommu_device has a 'struct device' embedded into
it, not as a pointer, but the whole struct. In the
conversion of the iommu drivers to use struct iommu_device
it was forgotten that the relase function for that struct
device simply calls kfree() on the pointer.

This frees memory that was never allocated and causes memory
corruption.

To fix this issue, use a pointer to struct device instead of
embedding the whole struct. This needs some updates in the
iommu sysfs code as well as the Intel VT-d and AMD IOMMU
driver.

Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Fixes: 39ab9555c2 ('iommu: Add sysfs bindings for struct iommu_device')
Cc: stable@vger.kernel.org # >= v4.11
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -4736,7 +4736,9 @@ static void intel_disable_iommus(void)
 
 static inline struct intel_iommu *dev_to_intel_iommu(struct device *dev)
 {
-	return container_of(dev, struct intel_iommu, iommu.dev);
+	struct iommu_device *iommu_dev = dev_to_iommu_device(dev);
+
+	return container_of(iommu_dev, struct intel_iommu, iommu);
 }
 
 static ssize_t intel_iommu_show_version(struct device *dev,