This is required to make sure that the constants in gps.h does not
ever go out of sync with the enums created out of them in the HAL
interface definition.
Test: mm
Change-Id: I103cf46d198e9f5de9e0cfd64f2795f0094ecb39
Enum sizes and names cleaned up, fixed errors in comments,
cleaned up some variable names.
Also removed AGnssRefLocation since it appears to be unused.
Bug:31974439
Test: mm
Change-Id: I88f43caac5ce9c7137e28b29ba55ea330786745f
A Debug interface as well as a configuration interface will be added in
another CL.
Bug: 31974439
Test: mma
Change-Id: I977d95fc815172bd2aae7c78f81e1fc7c9bce72a