[RESEND PATCH 4/7] dmaengine: sprd: Set cur_desc as NULL when free or terminate one dma channel

From: Eric Long It will be failed to start one new transfer if the channel started one none interrupt transfer before, since we will only set the schan->cur_desc as NULL depending on the transfer interrupt now. Thus we should set schan->cur_desc as NULL when free or terminate one dma channel to

[RESEND PATCH 4/7] dmaengine: sprd: Set cur_desc as NULL when free or terminate one dma channel

From: Eric Long It will be failed to start one new transfer if the channel started one none interrupt transfer before, since we will only set the schan->cur_desc as NULL depending on the transfer interrupt now. Thus we should set schan->cur_desc as NULL when free or terminate one dma channel to