Renamed enums in IGnssNavigationMessageCallback.hal from GNSS prefix to
GPS prefix; also made some comment fixes in IGnssMeasurementCallback.hal

BUG: 37946308
Test: Existing tests still pass.

Change-Id: Ia29c3f3943f0373e18634ddeede2ff5eb8998050
diff --git a/gnss/1.0/IGnssMeasurementCallback.hal b/gnss/1.0/IGnssMeasurementCallback.hal
index 467bf19..4031664 100644
--- a/gnss/1.0/IGnssMeasurementCallback.hal
+++ b/gnss/1.0/IGnssMeasurementCallback.hal
@@ -556,7 +556,7 @@
 
         /**
          * Signal-to-noise ratio at correlator output in dB.
-         * If the data is available, gnssClockFlags must contain MEASUREMENT_HAS_SNR.
+         * If the data is available, GnssMeasurementFlags must contain HAS_SNR.
          * This is the power ratio of the "correlation peak height above the
          * observed noise floor" to "the noise RMS".
          */