'contains' applies to arrays, but 'adi,dc-dc-mode' is a scalar. So drop
'contains' from the 'if' schema.
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20221111212846.4104059-1-robh@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>