[otbn,dv] Expand comments a bit in BadBNMovr generator
[otbn,dv] Expand comments a bit in BadBNMovr generator

No change in behaviour, but this should be a bit easier to understand.

Signed-off-by: Rupert Swarbrick <290093e2ad2515ed2f14d749293c8cf8e02ca274@lowrisc.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan