hal: compilation fix for extended feature flags

- Fix compilation error for offload, Dolby,
  HDMI pass through, FLAC decoder, and hardware
  accelerated effects when extended feature
  flags are disabled.

Change-Id: I5b36d7668f63a396ed930d62c0337c2c3f311c95
diff --git a/hal/msm8974/platform.c b/hal/msm8974/platform.c
index fc81443..eccf5b0 100644
--- a/hal/msm8974/platform.c
+++ b/hal/msm8974/platform.c
@@ -3197,6 +3197,11 @@
     return fragment_size;
 }
 
+bool platform_use_small_buffer(audio_offload_info_t* info)
+{
+    return OFFLOAD_USE_SMALL_BUFFER;
+}
+
 int platform_set_codec_backend_cfg(struct audio_device* adev,
                          snd_device_t snd_device,
                          unsigned int bit_width, unsigned int sample_rate)