We may disable proc fs only for sound part, to reduce ALSA
memory footprint. So add CONFIG_SND_PROC_FS and replace the
old CONFIG_PROC_FSs in alsa code.

With sound proc fs disabled, we can save about 9KB memory
size on X86_64 platform.
Signed-off-by: NJie Yang <yang.jie@intel.com>
Reviewed-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>