Tegra186 does not have master FIFO  control register and instead
uses FIFO control register like prior Tegra chipset.

This patch fixes this and prevents crashing during boot when
accessing FIFO control registers.
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>