iio: adc: ad_sigma_delta: change to buffer predisable

iio: adc: ad_sigma_delta: change to buffer predisable

commit 66d4374d97f85516b5a22418c5e798aed2606dec upstream.

Change the buffer disable callback from postdisable to predisable.
This balances the existing posteanble callback. Using postdisable
with posteanble can be problematic, for example, if update_scan_mode
fails, it would call postdisable without ever having called posteanble,
so the drivers using this would be in an unexpected state when
postdisable was called.

Fixes: af3008485ea0 ("iio:adc: Add common code for ADI Sigma Delta devices")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250703-iio-adc-ad_sigma_delta-buffer-predisable-v1-1-f2ab85138f1f@baylibre.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>