feat(stm32mp1): only fuse monotonic counter on closed devices

The fused monotonic counter is checked by the ROM bootloader. The ROM
bootloader won't allow booting images build with a lower
STM32_TF_VERSION value.

On non-closed devices a user can easily circumvent this. But it is
annoying for a developer when open development hardware gets the counter
value fused.

Signed-off-by: Robin van der Gracht <robin@protonic.nl>
Change-Id: Ie52561368a3178de9d9a44b9d089664241452651

plat/st/stm32mp1/bl2_plat_setup.c

@@ -367,7 +367,9 @@ skip_console_init:
 	print_reset_reason();
 
 #if STM32MP15
-	update_monotonic_counter();
+	if (stm32mp_check_closed_device() == STM32MP_CHIP_SEC_CLOSED) {
+		update_monotonic_counter();
+	}
 #endif
 
 	stm32mp1_syscfg_enable_io_compensation_finish();