stm32mp: fdt: update etzpc for STM32MP13x

Add support of STM32MP13x the ETZPC part of fdt.c

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Change-Id: If2777fbf66b8525a2a447056780aaa04e6b0a9a0