iio: adc: ad7791: fix IRQ flags

stable inclusion
from stable-v5.10.178
commit 4bfdead174438b815677c7fa2ebdf6139b5462ca
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8D927

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4bfdead174438b815677c7fa2ebdf6139b5462ca



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[ Upstream commit 0c6ef985 ]

The interrupt is triggered on the falling edge rather than being a level
low interrupt.

Fixes: da4d3d6b ("iio: adc: ad-sigma-delta: Allow custom IRQ flags")
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20230120124645.819910-1-nuno.sa@analog.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>