vboot_reference: fix CMOS writing for x86 platforms

VbCmosWrite should seek to correct offset before starting to write;
also fixed file handle leakage.

BUG=chromium-os:23000
TEST=crossystem recovery_request=1; echo $? # show: 0
     crossystem recovery_request # show: 1
     reboot # see recovery screen

Change-Id: I33bca8af2b351ba9b364309838df699a31bb543a
Reviewed-on: https://gerrit.chromium.org/gerrit/11756
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Commit-Ready: Hung-Te Lin <hungte@chromium.org>
1 file changed