sound: oss: remove driver for SGI HAL2 audio device

With the restructering of the indy button handling the old OSS HAL2 driver
got broken.  Since there is a new ALSA driver for HAL2, the experimental
OSS driver is obsolete and will be removed by this patch.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>