soc/tegra: fuse: Explicitly request DMA channel from APB DMA driver

Currently fuse driver requests DMA channel from an arbitrary DMA device,
it is not a problem since there is only one DMA provider for Tegra20 yet,
but it may become troublesome if another provider will appear.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>