stm32mp1: add stboard command

Allow to update board identification in OTP 59.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/board/st/stm32mp1/Makefile b/board/st/stm32mp1/Makefile
index 8188075..3c6c035 100644
--- a/board/st/stm32mp1/Makefile
+++ b/board/st/stm32mp1/Makefile
@@ -7,6 +7,7 @@
 obj-y += spl.o
 else
 obj-y += stm32mp1.o
+obj-$(CONFIG_CMD_STBOARD) += cmd_stboard.o
 endif
 
 obj-y += board.o