a2dp: Fix AAC frame size control

Remove incorrect member from AAC structure shared
with btaudio_offload.

Change-Id: I571927c9281a574b96756fe346fe903d5ae07d9a
diff --git a/hal/audio_extn/a2dp.c b/hal/audio_extn/a2dp.c
index 19c839c..c9ab383 100644
--- a/hal/audio_extn/a2dp.c
+++ b/hal/audio_extn/a2dp.c
@@ -678,7 +678,6 @@
     uint32_t sampling_rate;
     uint32_t bitrate;
     uint32_t bits_per_sample;
-    struct aac_frame_size_control_t frame_ctl;
 } audio_aac_encoder_config;
 #endif