tpm: move tpm1_pcr_extend to tpm1-cmd.c

Move tpm1_pcr_extend to tpm1-cmd.c and remove
unused pcrextend_header structure and
EXTEND_PCR_RESULT_SIZE and EXTEND_PCR_RESULT_BODY_SIZE
defines.

Fixes warning:
drivers/char/tpm/tpm-interface.c:609:38: warning: ‘pcrextend_header’ defined but not used [-Wunused-const-variable=]
 static const struct tpm_input_header pcrextend_header = {
                                      ^~~~~~~~~~~~~~~~

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Nayna Jain <nayna@linux.ibm.com>
Tested-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>