wallet_db: clarify hww types in old upgrades
wallet_db: clarify hww types in old upgrades

There is no point in adding new hww types to these lists every time support for a new hww is added.
These upgrades got released in 2.7.0 and any hw types added after are unrelated.

reverted to just-after last relevant change:
https://github.com/spesmilo/electrum/commit/c820423b00553913024ff8c2f54ac2fd5e3a9b89

pooler/electrum-ltc,pooler/electrum-ltc,pooler/electrum-ltc,spesmilo/electrum,spesmilo/electrum,spesmilo/electrum,pooler/electrum-ltc,spesmilo/electrum