arm: stm32mp: move dbgmcu_init call when DT is ready

As the dbgmcu_init use the function bsec_dbgswenable which is based
on the DM and DT, its call can't be done before the spl is initialized
(driver model, DT and malloc) in board_init_f::spl_early_init().

This function call is moved later in spl_board_init().

Fixes: bd3f60d29c24 ("arm: stm32mp: protect DBGMCU_IDC access with BSEC")

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/arch/arm/mach-stm32mp/Kconfig b/arch/arm/mach-stm32mp/Kconfig
index 4003c2e..478fd2f 100644
--- a/arch/arm/mach-stm32mp/Kconfig
+++ b/arch/arm/mach-stm32mp/Kconfig
@@ -1,6 +1,7 @@
 if ARCH_STM32MP
 
 config SPL
+	select SPL_BOARD_INIT
 	select SPL_CLK
 	select SPL_DM
 	select SPL_DM_SEQ_ALIAS