plat/st: Add SSP support for STM32CubeProgrammer

Add STM32CubeProgrammer communication update for SSP support.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Change-Id: I1830bff82d87b3535f0787eb5f47c56960feccaa
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/tf-a/+/185335


Reviewed-by: CITOOLS <smet-aci-reviews@lists.codex.cro.st.com>
Reviewed-by: Lionel DEBIEVE <lionel.debieve@st.com>
Reviewed-by: Yann GAUTIER <yann.gautier@st.com>
Tested-by: Lionel DEBIEVE <lionel.debieve@st.com>