iio: accel: adxl345: introduce adxl345_push_event function

Move the fifo handling into a separate function. This is a preparation
for a generic handling of the interrupt status register results. The
function is supposed to handle particular sensor events, and later to
forward them to the iio channel. This is needed to read out the interrupt
status register.

The function shall return occurring errors, if any, or 0 in case of
handled events or read fifo content. Thus migrate fifo read-out and push
fifo content to iio channels into this function to be built up with
additional event handling.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
Link: https://patch.msgid.link/20250414184245.100280-2-l.rubusch@gmail.com


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