dmaengine: tegra: fix incompatible pointer type warns

drivers/dma/tegra20-apb-dma.c:1428:37: warning: assignment from incompatible pointer type [enabled by default]
drivers/dma/ste_dma40.c: In function 'd40_terminate_all':

The function prototype expects return type 'int' whereas these where void

Signed-off-by: Vinod Koul <vinod.koul@intel.com>