clk: tegra: Add peripheral registers for bank Y

Tegra210 has an extra bank of peripheral clock registers. Add it to the
generic peripheral clock code.

Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: Prashant Gaikwad <pgaikwad@nvidia.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>