hwdb: change definition of PROXIMITY_NEAR_LEVEL for sensors

hwdb: change definition of PROXIMITY_NEAR_LEVEL for sensors

The [kernel documentation][0] for the in_proximity_nearlevel sysfs
attribute on iio proximity devices states:

    If the value read from the sensor is above or equal to the value in
    this file an object should typically be considered near.

Meaning a 'greater than or equal to' comparison.

Make the documentation comment in 60-sensors.hwdb suggest a
greater-or-equal rather than a strict greater-than comparison.

[0]: https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-bus-iio-proximity

Fixes #25793