clk: tegra114: Rename gr_2d/gr_3d to gr2d/gr3d

These clocks were named gr2d and gr3d on Tegra20 and Tegra30, so use the
same names on Tegra114 for consistency.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>