clk: tegra: move from a lock bit idx to a lock mask

PLLC2 and PLLC3 on Tegra114 have separate phaselock and frequencylock bits.
So switch to a lock mask to be able to test both at the same time.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>