tpm/tpm_ftpm_tee: support TPM_CHIP_FLAG_SYNC

This driver does not support interrupts, and receiving the response is
synchronous with sending the command.

Enable synchronous send() with TPM_CHIP_FLAG_SYNC, which implies that
->send() already fills the provided buffer with a response, and ->recv()
is not implemented.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>