stagefright: Fix profile/level override for encoder

In absence of a valid profile and level set for encoding;
Override _both_ profile and level. Not doing so will fail
an error check.

Remove the legacy code in ACodec which forces AVC profile
to baseline always (though encoder seems to support higher).

Apply custom decoder settings to decoder only.

CRs-Fixed: 694961
Change-Id: Ie0c81833569410db8b8470a553009bf27a7f7c27
Conflicts:
media/libstagefright/ACodec.cpp