Avoid unintentional sign conversions in lppTransposer() and lppTransposerHBE().

Bug: 186777497
Test: atest android.media.cts.DecoderTestAacFormat android.media.cts.DecoderTestXheAac android.media.cts.DecoderTestAacDrc
Change-Id: Ifc4618b8de4e377df28e387fb976ab5acb5883d7
1 file changed