The previous implementation used creative construct for impedance
mismatching between the core list API (which returns a ptr to the
removed element if found) and the GNRC pkt list API (which returns a
ptr to the new list head) that creates a temporary list head on the
stack.
I'm not entirely sure if the previous implementation is containing
undefined behavior that is used against us with GCC >= 12.x, or if this
is a compiler bug. In either case, not reusing the core list API here
and just having a textbook linked list delete function here is not much
less readable and fixes the issue for our users.
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