refactor(st): move some storage definitions to common part

Those storage macros are common to all STM32MPU chips, move them to
plat/st/common/include/stm32mp_io_storage.h

Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Change-Id: Id20ec00ba65edf9ec7a3a89adfda307c954c3cb6
5 files changed