iio: adc: ad_sigma_delta: Check for previous ready signals
It can happen if a previous conversion was aborted the ADC pulls down
the R̅D̅Y̅ line but the event wasn't handled before. In that case enabling
the irq might immediately fire (depending on the irq controller
capabilities) and even with a rdy-gpio isn't identified as an unrelated
one.
To cure that problem check for a pending event before the measurement is
started and clear it if needed.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/3ec6b61fb1e527e935133dc56f589aab4b2094a3.1733504533.git.u.kleine-koenig@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>