clk: tegra: don't warn for pll_d2 defaults unnecessarily

If the PLL is on, only warn if the defaults are not yet set. Otherwise be
silent.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Reviewed-by: Timo Alho <talho@nvidia.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>