The cros-ec-accel devices report their mounting location by the 'label'
sysfs file only since Linux v6.0. With earlier kernels, a nonstandard
'location' file reports this, but slightly differently (lid instead of
display) [1].
Add udev rules to import the correct hwdb entries based on this
'location' file for cros-ec-accel devices, so that the base-mounted
accel matrix has the correct value for older kernels as well.
[1] https://kernel.org/doc/Documentation/ABI/testing/sysfs-bus-iio-cros-ec
The IIO subsystem exposes a 'label' sysfs file to help userspace better
identify its devices [1]. Standardized labels include the sensor type
along with its location, including 'accel-base' and 'accel-display'.
Most Chrome OS boards have two accelerometers that are indistinguishable
except for this label (or a 'location' sysfs file before Linux v6.0),
and need different mounting matrix corrections based on their location.
Add a udev rule that matches hwdb entries using this label, so we can
correct both accelerometers on these devices with hwdb entries. The
existing rules and hwdb entries are not modified to keep potential
out-of-tree entries working, but new entries in this form will override
existing ones. Also add currently standardized labels to parse-hwdb.py.
[1] https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-iio
This change is only about the source tree. We have tmpfiles.d/, modprobe.d/,
sysctl.d/, and sysusers.d/, but for historical reasons, rules/ didn't fit this
pattern. We also *install* it as rules.d/. Let's rename to be consistent.
