iio: adc: ad7606: Switch to sparse friendly iio_device_claim/release_direct()

These new functions allow sparse to find failures to release
direct mode reducing chances of bugs over the claim_direct_mode()
functions that are deprecated.

This driver got partly converted during removal of the _scoped form.
However some more cases got added in parallel.

Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250217141630.897334-15-jic23@kernel.org


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>