configs: stm32: Remove BOARD_EARLY_INIT_F and BOARD_LATE_INIT for stm32 boards

These flags was defined and callbacks linked to these flags are empty
and only returning 0.
Remove BOARD_EARLY_INIT_F and BOARD_LATE_INIT flags for these stm32 boards.

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