dmaengine/dw_dmac: don't call callback routine in case dmaengine_terminate_all() is called

If dmaengine_terminate_all() is called for dma channel, then it doesn't make
much sense to call registered callback routine. While in case of success or
failure it must be called.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>