Use proper struct initializers and remove INIT_FIELD() macro

Signed-off-by: Juan Quintela <quintela@redhat.com>
diff --git a/audio/sdlaudio.c b/audio/sdlaudio.c
index dafef5d..6870fdf 100644
--- a/audio/sdlaudio.c
+++ b/audio/sdlaudio.c
@@ -440,15 +440,15 @@
 };
 
 struct audio_driver sdl_audio_driver = {
-    INIT_FIELD (name           = ) "sdl",
-    INIT_FIELD (descr          = ) "SDL http://www.libsdl.org",
-    INIT_FIELD (options        = ) sdl_options,
-    INIT_FIELD (init           = ) sdl_audio_init,
-    INIT_FIELD (fini           = ) sdl_audio_fini,
-    INIT_FIELD (pcm_ops        = ) &sdl_pcm_ops,
-    INIT_FIELD (can_be_default = ) 1,
-    INIT_FIELD (max_voices_out = ) 1,
-    INIT_FIELD (max_voices_in  = ) 0,
-    INIT_FIELD (voice_size_out = ) sizeof (SDLVoiceOut),
-    INIT_FIELD (voice_size_in  = ) 0
+    .name           = "sdl",
+    .descr          = "SDL http://www.libsdl.org",
+    .options        = sdl_options,
+    .init           = sdl_audio_init,
+    .fini           = sdl_audio_fini,
+    .pcm_ops        = &sdl_pcm_ops,
+    .can_be_default = 1,
+    .max_voices_out = 1,
+    .max_voices_in  = 0,
+    .voice_size_out = sizeof (SDLVoiceOut),
+    .voice_size_in  = 0
 };