Remove unnecessary null pointer checks

[elfring]

An extra null pointer check is not needed in functions like the following.

• Device
• HostProxy_GadgetFS
• Interface
• InterfaceGroup
• Manager

[dominicgs]

Yes, there's a lot that can be cleaned up here, we could also use delete[] rather than looping over those arrays.

[elfring]

Are there a few update candidates left over?

[dominicgs]

Good point!