ARM: stm32: Add fitImage its entry for 587-200 DHCOR SoM

The new 587-200 DHCOR SoM is compatible with the 587-100 prototype,
hence just replicate the entries, as there is no pattern matching.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>