iio: adis: handle devices that cannot unmask the drdy pin

Some devices can't mask/unmask the data ready pin and in those cases
each driver was just calling '{dis}enable_irq()' to control the trigger
state. This change, moves that handling into the library by introducing
a new boolean in the data structure that tells the library that the
device cannot unmask the pin.

On top of controlling the trigger state, we can also use this flag to
automatically request the IRQ with 'IRQF_NO_AUTOEN' in case it is set.
So far, all users of the library want to start operation with IRQs/DRDY
pin disabled so it should be fairly safe to do this inside the library.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20210903141423.517028-3-nuno.sa@analog.com


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