fix(plat/st): only check header major when booting

An STM32 image with the awaited header major version shouldn't be forbid
to boot. If the minor differs, then it means only non-mandatory options
have been added in the reserved fields, and the header remains backward
compatible.

Change-Id: Iff16b67f95c728e2f1d128bd1760a4be497c5ca3
Signed-off-by: Yann Gautier <yann.gautier@st.com>
1 file changed