blocks/sectors != blocks/blocks. Fix calculation of b_cylinder in bounds_check_with_label(). Tweak error path to eliminate duplicate code.
blocks/sectors != blocks/blocks. Fix calculation of b_cylinder in
bounds_check_with_label(). Tweak error path to eliminate duplicate
code.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars