scripts: gen_kobject_list.py: Simplify test with chained comparison

'a < b and b < c' can be simplified to 'a < b < c' in Python.

Fixes this pylint warning:

    scripts/gen_kobject_list.py:198:22: R1716: Simplify chained
    comparison between the operands (chained-comparison)

Fixing pylint warnings for a CI check.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>