[ALSA] PCM midlevel & PCM OSS - make procfs & OSS plugin code optional

Modules: ALSA Core,PCM Midlevel,ALSA<-OSS emulation,USB generic driver

1) The verbose procfs code for the PCM midlevel and usb audio
   can be removed now (more patches will follow).
   CONFIG_SND_VERBOSE_PROCFS
2) The PCM OSS plugin system can be also compiled optionaly.
   CONFIG_SND_PCM_OSS_PLUGINS

Signed-off-by: Jaroslav Kysela <[email protected]>

include/sound/pcm_oss.h

@@ -56,8 +56,10 @@ struct snd_pcm_oss_runtime {
 	size_t mmap_bytes;
 	char *buffer;				/* vmallocated period */
 	size_t buffer_used;			/* used length from period buffer */
+#ifdef CONFIG_SND_PCM_OSS_PLUGINS
 	struct snd_pcm_plugin *plugin_first;
 	struct snd_pcm_plugin *plugin_last;
+#endif
 	unsigned int prev_hw_ptr_interrupt;
 };