Disable armnn nnapi backend

Discontinue maintenance and active support of ArmNN on Pixel phones.

Bug: 294459623
Test: Local nnapi_info
Merged-In: I3eb3f880671bea091ff6c798d8def2f559a5e291
Change-Id: Ib6140584a724b5e1fd3634e414773092da49b41a
1 file changed