Move ST2 reading with overflow handling after measurement data
reading.
ST2 register read have to be read after read measurment data,
because it means end of the reading and realease the lock on the data.
Remove ST2 read skip on interrupt based waiting because ST2 required to
be read out at and of the axis read.

Fixes: 57e73a42 ("iio: ak8975: add ak09911 and ak09912 support")
Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
Link: https://patch.msgid.link/20240819-ak09918-v4-2-f0734d14cfb9@mainlining.org
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>