Make sure mTransmitPowerInfo is always populated

Currently mTransmitPowerInfo could be empty, which ends up with a
IndexOutOfBoundsException.

Bug: 141382585
Change-Id: I97417f539b2bfba98499cbf4b609ea7c088b808f
Test: atest CtsIncidentHostTestCases:com.android.server.cts.BatteryStatsValidationTest
1 file changed