cr50: fix hash database parser to reject misformatted offsets/sizes
cr50: fix hash database parser to reject misformatted offsets/sizes

Section offsets and sizes are hex numbers which should not be longer
than 8 characters.

BRANCH=none
BUG=b:73668125

TEST=descriptions which miss the size field are properly reported now.
     Before the utility would just terminate with an error without a
     message.

Change-Id: I9bc461b5f848b80e464fecc9b40dcf0ea213c9a7
Signed-off-by: Vadim Bendebury <5515d6d2d0829cbe0dd0dcf2094aaded06d58514@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/949311
Reviewed-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec