[otbn] Push design to the development (L1) lifecycle
[otbn] Push design to the development (L1) lifecycle

The design has been past its specification stage for a while now, and
we've reached D1 on the design. This means we should also be in L1 for
the overall lifecycle, indicating that the design is "Under
Development".

Signed-off-by: Philipp Wagner <5a4b10454c30419e54a1570be358a516ff84bb63@lowrisc.org>

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