[otbn,rtl] Fix timing of locking signal from controller
[otbn,rtl] Fix timing of locking signal from controller

Commit 2aa877f *still* didn't quite get the timing of the locking
signal right. It squashed the single-cycle glitch at the start of the
secure wipe, but left another one at the end. This simple patch sorts
things out at both ends.

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

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