clk: tegra: Update T210 PLLSS (D2/DP) registration

Remove from Tegra210 PLLSS registration code sections that
- attempt to set PLL minimum rate (unnecessary, and dangerous if PLL
  is already enabled on boot)
- apply pre-Tegra210 defaults settings
- check IDDQ setting (duplicated with Tegra210 PLLSS check defaults)

Replaced setting of reference clock with check that default oscillator
selection is not changed, and failed registration otherwise as validation
was only done with the oscillator as the reference clock.

Reordered registration, so that PLL initialization is called after
VCOmin adjustment.

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