staging: iio: resolver: ad2s1210: refactor sample toggle

staging: iio: resolver: ad2s1210: refactor sample toggle

This refactors the sample line toggle in the ad2s1210 resolver driver
to a separate function. The sample has some timing requirements, so
this ensures that it is always done the same way, both in the existing
call sites and any future usage.

Previously, the sample line was kept on for the duration of the read,
but this is not necessary. Data is latched in on the rising edge and
after the specified delay the state of the sample line does not matter.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20231010-ad2s1210-mainline-v5-1-35a0f6ffa04a@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>