Remove @space from tpm_transmit() API` in order to completely remove the
bound between low-level transmission functionality and TPM spaces. The
only real dependency existing is the amount of data saved before trying
to send a command to the TPM.

It doesn't really matter if we save always a bit more than needed so
this commit changes the amount saved always to be the size of the TPM
header and three handles.

Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Tested-by: Alexander Steffen <Alexander.Steffen@infineon.com>