tpm: Keep the active PCRs in the chip private data

tpm: Keep the active PCRs in the chip private data

We have a lot of code trying to reason about the active TPM PCRs
when creating an EventLog. Since changing the active banks can't
be done on the fly and requires a TPM reset,  let's store them
in the chip private data instead.

Upcoming patches will use this during the EventLog creation.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>