fix(st): provide DT file for STM32MP13

Whereas the device tree file should not be required to compile only BL2
on ST platforms, the coverity script fails because it tries to use the
default DT file (dedciated to STM32MP15). Provide STM32MP13 DT file
to the command line to avoid the issue.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I12031bee697dd28bf3809c552a59cf5312a09e36
1 file changed