tpm: fine-tune assignment in tpm_transmit_cmd()

Removed unnecessary cast to this form:

header = cmd;

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
tpm: remove redundant PPI_VERSION constant from tpm_ppi.c

PPI_VERSION constant has been replaced with TPM_PPI_VERSION
constant. Changed size calculation in strlcpy() to use
sizeof(chip->ppi_version) instead of PPI_VERSION + 1.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>