libstagefright: use appropriate hevc decoder on 8916 and 8939

8916 supports HEVC software decoder and 8939 support h/w decoder.
Based on media.swhevccodectype and media.hwhevccodectype properties values
instantiate appropriate HEVC decoder.

Change-Id: Ic3d37e6184db256f4d83bfe74b67271b20f94ec0
libstagefright: HSR: Read framerate from HSR key

- HSR and HFR keys are made mutually exclusive now.
- In case of HSR, HSR key will be set with requested frame rate and
  HFR key is not set.
- In case of HFR, HFR key will be set with requested frame rate and
  HSR key is not set.
- Check
     if video-hfr key is set
        set kKeyHFR with HFR key value passed by camera
     else check video-hsr key, if set
        set kKeyHSR with HSR key value passed by camera

Change-Id: Ic7ad098137812ad78afdc326334fa390404075fc