dmaengine: sirf: set dma residue based on the current dma transfer position

read SIRFSOC_DMA_CH_ADDR register to get current dma transfer position, then
update dma residue so that things like ALSA drivers work as ALSA drivers need
the right residue value.

Signed-off-by: Rongjun Ying <Rongjun.Ying@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>