[e.cash] Fix Trezor description

Summary: All Trezor models support eCash for regular use, Stake signing is the part that doesn't work on Model One

Test Plan: run it locally, read description

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D18278