SOUND-OSS: Remove sh_dac_audio

Remove the SH DAC oss driver since there is an equivalent alsa driver.
oss has been deprecated for years. Furthermore this driver has BKL code
which we are trying to remove. Rather than attempt to fix this, simply
remove the driver.

Signed-off-by: John Kacur <jkacur@redhat.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>