ARM: tegra: Add Tegra20 host1x clock support

Extend the pll_d frequency table with a few entries to support common
HDMI and LVDS display modes and setup the clock parents for the two
display controllers and HDMI.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Stephen Warren <swarren@nvidia.com>