dmaengine: at_xdmac: fix bad behavior in interleaved mode

When performing interleaved transfers with numf > 1, an extra line is
copied. The mbr.bc field is incremented once too often. The length of
the block is (BLEN+1) microblocks.
Signed-off-by: Sylvain ETIENNE <Sylvain.ETIENNE@ingenico.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Fixes: 4e538578 ("dmaengine: at_xdmac: handle numf > 1")
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/at_xdmac.c

@@ -965,7 +965,9 @@ at_xdmac_prep_interleaved(struct dma_chan *chan,
 							NULL,
 							src_addr, dst_addr,
 							xt, xt->sgl);
-		for (i = 0; i < xt->numf; i++)
+
+		/* Length of the block is (BLEN+1) microblocks. */
+		for (i = 0; i < xt->numf - 1; i++)
 			at_xdmac_increment_block_count(chan, first);
 
 		dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",