libstagefright: Fix for video can't be played if BT is connected

-Issue: Video can't be played if BT is connected.
-Rootcause: Source code to handle fallback to software decoder
 if offload audio track creation fails is not present.
-Fix: Add source code to handle fallback to software decoder
 if offload audio track creation fails.

Change-Id: Ie136a2117dd3f028c962b8b73ebc238bc982d79b
CRs-Fixed:  593230
libstagefright: adjust AV sync late margin based on property

- Current AV late margin is 40 ms
- Read system property media.sf.set.late.margin and if
  new AV sync late margin is set then use the same
- Max AV sync late margin allowed is 250 ms
- Min AV sync late margin is default 40 ms

Change-Id: I65cd3dce9b31b87f1488c37af9618669b29c362c
av: Cleanup a lot of QCOM cruft

 * Remove some legacy code to bring us closer to kk_3.5

Change-Id: I5c2ec1b7da9281adfcb1eb6ff9ca71d423a2e07b