Changes

Fix lint errors: avoid equality comparisons to `False`

src/osmocom/utils.py:150:8: E712 Avoid equality comparisons to `False`; use `if not signed:` for false checks
    |
148 |     """
149 |
150 |     if signed == False and number < 0:
    |        ^^^^^^^^^^^^^^^ E712
151 |         raise ValueError("expecting a positive number")
    |
    = help: Replace with `not signed`

Change-Id: I2ebb33c498b4a7e6229980462aa51b579fa4f782