dmaengine: tegra-apb: Free interrupts before killing tasklets

On probe failure or driver removal, before killing any tasklets, ensure
that the channel interrupt is freed to ensure that another channel
interrupt cannot occur and schedule the tasklet again.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>