feat(plat/st): add a function to configure console

To ease console configuration, a dedicated function is created:
stm32mp_uart_console_setup(). The code will also be common for the
different BLs.

Change-Id: Idf3cad756f125ca2313cf30b1311637a9df8f27f
Signed-off-by: Yann Gautier <yann.gautier@st.com>
2 files changed