stagefright: Fix MediaCodecList

 * Missed a few 32->64 conversions in the switch to handle additional
   media types.

Change-Id: I06e26f27576cbf2780a54e3e577209c22fc887b4
stagefright: Only use HW AAC for AV content

 * While this decoder can handle more streams, it can't handle gapless.

Change-Id: I60cb3ca56c57a1280ca0805976e766e242ac1744