tpm: move length validation to tpm_transmit()

Check that the length matches the length reported by the response
header already in tpm_transmit() to improve validation.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>