tpm/tpm_i2c_stm_st33: Add new tpm_stm_dev structure and remove tpm_i2c_buffer[0], [1] buffer.

In order to clean big buffers in st33zp24_platform_data structure,
replace with tpm_stm_dev for driver internal usage.
As only one buffer is really necessary replace with buf field.

In the mean time move tpm_i2c_stm_st33.h to include/linux/platform_data.

Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>