iommu/msm: ->unmap() should return order of unmapped page

Users of the IOMMU API (kvm specifically) assume that iommu_unmap()
returns the order of the unmapped page (on success).

Fix msm_iommu_unmap() accordingly.
Signed-off-by: NOhad Ben-Cohen <ohad@wizery.com>
Cc: Stepan Moskovchenko <stepanm@codeaurora.org>
Cc: David Brown <davidb@codeaurora.org>
Acked-by: NDavid Brown <davidb@codeaurora.org>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>

drivers/iommu/msm_iommu.c

@@ -543,6 +543,13 @@ static int msm_iommu_unmap(struct iommu_domain *domain, unsigned long va,
 	}
 
 	ret = __flush_iotlb(domain);
+
+	/*
+	 * the IOMMU API requires us to return the order of the unmapped
+	 * page (on success).
+	 */
+	if (!ret)
+		ret = order;
 fail:
 	spin_unlock_irqrestore(&msm_iommu_lock, flags);
 	return ret;