tpm: move tpm_chip definition to include/linux/tpm.h

The tpm_chip structure contains the list of PCR banks currently allocated
in the TPM. When support for crypto agility will be added to the TPM
driver, users of the driver have to provide a digest for each allocated
bank to tpm_pcr_extend(). With this patch, they can obtain the PCR bank
algorithms directly from chip->allocated_banks.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>