binman: Write symbol info before image inclusion

binman: Write symbol info before image inclusion

At present the symbol information is written to binaries just before
binman exits. This is fine for entries within sections since the section
contents is calculated when it is needed, so the updated symbol values are
included in the image that is written.

However some binaries are inside entries which have already generated
their contents and do not notice that the entries have changed (e.g. Intel
IFWI).

Move the symbol writing earlier to cope with this.

Signed-off-by: Simon Glass <sjg@chromium.org>