feat(st): add the TRUSTED_BOARD_BOOT build config

Add the TRUSTED_BOARD_BOOT option for the STM32MP15 and
STM32MP13 boards.
It will includes the specific files to manage authentication
and decryption.
Add two specific STM32MP13 configurations to use ECDSA Brainpool
algorithms.

Signed-off-by: Lionel Debieve <lionel.debieve@foss.st.com>
Change-Id: I25e79b79e8cee067524fece148c4cb3a5c79d7f0
diff --git a/tf_config/stm32mp1-tbb b/tf_config/stm32mp1-tbb
new file mode 100644
index 0000000..86d65fc
--- /dev/null
+++ b/tf_config/stm32mp1-tbb
@@ -0,0 +1,9 @@
+AARCH32_SP=sp_min
+ARCH=aarch32
+ARM_ARCH_MAJOR=7
+CROSS_COMPILE=arm-none-eabi-
+PLAT=stm32mp1
+STM32MP_EMMC=1
+STM32MP_SDMMC=1
+DTB_FILE_NAME=stm32mp157c-ev1.dtb
+TRUSTED_BOARD_BOOT=1