board: st: Add support of STM32MP13x boards in stm32board cmd

Add board identifiers for STMicroelectronics STM32MP13x boards:
- DISCO board: MB1635

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/board/st/common/Kconfig b/board/st/common/Kconfig
index 2f57118..aba3590 100644
--- a/board/st/common/Kconfig
+++ b/board/st/common/Kconfig
@@ -1,7 +1,7 @@
 config CMD_STBOARD
 	bool "stboard - command for OTP board information"
 	depends on ARCH_STM32MP
-	default y if TARGET_ST_STM32MP15x
+	default y if TARGET_ST_STM32MP15x || TARGET_ST_STM32MP13x
 	help
 	  This compile the stboard command to
 	  read and write the board in the OTP.