board: stm32mp1: Fix warnings when compiling with W=1

This patch solves the following warnings:

warning: no previous prototype for 'board_quiesce_devices' [-Wmissing-prototypes]
 void board_quiesce_devices(void)
      ^~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
1 file changed