[ALSA] Optimize for config without PROC_FS (seq and oss parts)

Modules: ALSA<-OSS emulation,ALSA sequencer,ALSA<-OSS sequencer

Optimize the code when compiled without CONFIG_PROC_FS (in seq and oss
emulation parts).

Signed-off-by: Takashi Iwai <tiwai@suse.de>