dmaengine: sun6i: fix the uninitialized value for v_lli

dma_pool_alloc does not initialize the value of the newly allocated
block for the v_lli, and the uninitilize value make the tests failed
which is on pine64 with dmatest.
we can fix it just change the "|=" to "=" for the v_lli->cfg.

Signed-off-by: Hao Zhang <hao5781286@gmail.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/sun6i-dma.c

@@ -578,7 +578,7 @@ static struct dma_async_tx_descriptor *sun6i_dma_prep_dma_memcpy(
 
 	burst = convert_burst(8);
 	width = convert_buswidth(DMA_SLAVE_BUSWIDTH_4_BYTES);
-	v_lli->cfg |= DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
+	v_lli->cfg = DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
 		DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
 		DMA_CHAN_CFG_DST_LINEAR_MODE |
 		DMA_CHAN_CFG_SRC_LINEAR_MODE |