dmaengine, async_tx: support alignment checks

Some engines have transfer size and address alignment restrictions.  Add
a per-operation alignment property to struct dma_device that the async
routines and dmatest can use to check alignment capabilities.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
index db27987..b459a90 100644
--- a/crypto/async_tx/async_xor.c
+++ b/crypto/async_tx/async_xor.c
@@ -193,7 +193,7 @@
 	else if (sizeof(dma_addr_t) <= sizeof(struct page *))
 		dma_src = (dma_addr_t *) src_list;
 
-	if (dma_src && chan) {
+	if (dma_src && chan && is_dma_xor_aligned(chan->device, offset, 0, len)) {
 		/* run the xor asynchronously */
 		pr_debug("%s (async): len: %zu\n", __func__, len);
 
@@ -265,7 +265,8 @@
 	else if (sizeof(dma_addr_t) <= sizeof(struct page *))
 		dma_src = (dma_addr_t *) src_list;
 
-	if (dma_src && device && src_cnt <= device->max_xor) {
+	if (dma_src && device && src_cnt <= device->max_xor &&
+	    is_dma_xor_aligned(device, offset, 0, len)) {
 		unsigned long dma_prep_flags = 0;
 		int i;