bank-payment/account_payment_mode/views/account_journal.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
    <record id="view_account_journal_form" model="ir.ui.view">
        <field name="name">usability.account_journal.form</field>
        <field name="model">account.journal</field>
        <field name="inherit_id" ref="account.view_account_journal_form" />
        <field name="arch" type="xml">
            <!-- better when related fields are readonly, otherwise the user
                 doesn't understand that he is changing the bank_id
                 on the underlying res.partner.bank object -->
            <field name="bank_id" position="attributes">
                <attribute name="readonly">1</attribute>
            </field>
        </field>
    </record>
</odoo>