Make input and output of find_section const, and fix the fallout. We
shouldn't modify the VBT, so make the compiler help us here.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>