feat(stm32mp1): retry 3 times FWU trial boot

If we reboot 3 times in trial mode, BL2 will select previous boot image.

Signed-off-by: Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>
Change-Id: I82b423cc84f0471fdb6fa7c393fc5fe411d25c06
diff --git a/plat/st/common/include/stm32mp_common.h b/plat/st/common/include/stm32mp_common.h
index d8d1c13..0010cd8 100644
--- a/plat/st/common/include/stm32mp_common.h
+++ b/plat/st/common/include/stm32mp_common.h
@@ -129,6 +129,8 @@
 
 #if !STM32MP_USE_STM32IMAGE && PSA_FWU_SUPPORT
 void stm32mp1_fwu_set_boot_idx(void);
+uint32_t stm32_get_and_dec_fwu_trial_boot_cnt(void);
+void stm32_set_max_fwu_trial_boot_cnt(void);
 #endif /* !STM32MP_USE_STM32IMAGE && PSA_FWU_SUPPORT */
 
 #endif /* STM32MP_COMMON_H */