hal: fix compilation issues with audio FM extention

- Update FM device references to match latest
  definitions to fix compilation of FM extention.
- Update FM feature flag for power optimization.

Change-Id: I17a9e240e552c4089d3e9c7a25e437fb5b5433f9
diff --git a/hal/audio_extn/fm.c b/hal/audio_extn/fm.c
index ed3776c..61c21d2 100644
--- a/hal/audio_extn/fm.c
+++ b/hal/audio_extn/fm.c
@@ -31,7 +31,7 @@
 #include <stdlib.h>
 #include <cutils/str_parms.h>
 
-#ifdef FM_ENABLED
+#ifdef FM_POWER_OPT
 #define AUDIO_PARAMETER_KEY_HANDLE_FM "handle_fm"
 #define AUDIO_PARAMETER_KEY_FM_VOLUME "fm_volume"
 #define AUDIO_PARAMETER_KEY_REC_PLAY_CONC "rec_play_conc_on"
@@ -299,4 +299,4 @@
 exit:
     ALOGV("%s: exit", __func__);
 }
-#endif /* FM_ENABLED end */
+#endif /* FM_POWER_OPT end */