tpm: tis: add support for MMIO TPM on SynQuacer

When fitted, the SynQuacer platform exposes its SPI TPM via a MMIO
window that is backed by the SPI command sequencer in the SPI bus
controller. This arrangement has the limitation that only byte size
accesses are supported, and so we'll need to provide a separate module
that take this into account.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>