binman: Update intel_ifwi to store padded section

With a recent change this entry stores only part of the section data,
leaving out the padding at the end. Fix this by using GetPaddedData() to
get the data. Add this function to the base Entry class also.

Fixes: d1d3ad7d1fe ("binman: Move section padding to the parent")

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