arm: stm32mp: move code for STM32MP15x

Move code and defines only needed for CONFIG_STM32MP15x in stm32mp15x.c
when low level init without TFABOOT is supported.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
6 files changed