Enable config for dmaengine based Tegra APB DMA driver and
disable the legacy APB DMA driver (SYSTEM_DMA).

[swarren: removed CONFIG_TEGRA_SYSTEM_DMA not set line, since the option
is removed entirely in a later patch]
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>