iommu/virtio: Fix typo in a comment

The double `as' in a comment is repeated, thus it should be removed.
Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Link: https://lore.kernel.org/r/20211216083302.18049-1-wangxiang@cdjrlc.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/virtio-iommu.c

@@ -743,7 +743,7 @@ static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev)
 
 	/*
 	 * In the virtio-iommu device, when attaching the endpoint to a new
-	 * domain, it is detached from the old one and, if as as a result the
+	 * domain, it is detached from the old one and, if as a result the
 	 * old domain isn't attached to any endpoint, all mappings are removed
 	 * from the old domain and it is freed.
 	 *