feat(st): use stm32_get_otp_value_from_idx() in BL31

The shadowing of the OTP is done in BL2.
As for BL32 on AARCH32 systems, stm32_get_otp_value_from_idx()
should also use bsec_read_otp() in BL31.

Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Change-Id: Ib406cfc154339e6d3cde3c925bc6e9416d77b689

plat/st/common/stm32mp_common.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2023, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -169,7 +169,7 @@ int stm32_get_otp_value_from_idx(const uint32_t otp_idx, uint32_t *otp_val)
 
 #if defined(IMAGE_BL2)
 	ret = bsec_shadow_read_otp(otp_val, otp_idx);
-#elif defined(IMAGE_BL32)
+#elif defined(IMAGE_BL31) || defined(IMAGE_BL32)
 	ret = bsec_read_otp(otp_val, otp_idx);
 #else
 #error "Not supported"