clk: tegra: Enable PLL_SS for Tegra210

Make sure the pll_ss ops are compiled even when only building for Tegra210.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Reviewed-by: Shreshtha Sahu <ssahu@nvidia.com>
Tested-by: Shreshtha Sahu <ssahu@nvidia.com>
Reviewed-by: Jon Mayo <jmayo@nvidia.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>