dmaengine: dmatest: Apply copy_align to DMA_SG as well

The DMA_SG is still a type of memory copy operation that should
conform the hardware restriction. So this patch just applies the
copy_align to DMA_SG as well.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>