fix(stm32mp2): use TOOL_ADD_IMG_PAYLOAD for BL31 DT

Use TOOL_ADD_IMG_PAYLOAD instead of TOOL_ADD_IMG to generate the BL31
device tree blob to be included in FIP. This allows building all TF-A
binaries and FIP in a single command. Else, as TOOL_ADD_IMG evaluate
the existence of the file before building it, we have a build error.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I72d2f70733c49792d0321ad07f5a3bbd283a36d4
1 file changed