Remove isUpdatable query from NNAPI -- hal

The NNAPI originally planned to have updated platform drivers delivered
through GMSCore. These updatable drivers would be retrieved through the
NN sAIDL utility code, and were known to be updatable through
Manager.cpp's Device::isUpdatable query.

However, the NNAPI ultimately did not move forward with its updatability
plans. This CL removes the updatability check in the NN AIDL utility
code.

Bug: N/A
Test: mma
Test: CtsNNAPITestCases
Test: NeuralNetworksTest_static
Change-Id: I6f9c1eac3af8cb54565bfaaeab7ddd382a85e3bd