sound: oss: sh_dac_audio timer fixes.

This patch modifies sh_dac_audio in the following ways:

- use high resolution timer instead of TMU1
- fix cpu/dac.h include
- add future rewrite comment

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/sound/oss/Kconfig b/sound/oss/Kconfig
index 1ca7427..bcf2a06 100644
--- a/sound/oss/Kconfig
+++ b/sound/oss/Kconfig
@@ -561,7 +561,7 @@
 
 config SOUND_SH_DAC_AUDIO
 	tristate "SuperH DAC audio support"
-	depends on CPU_SH3
+	depends on CPU_SH3 && HIGH_RES_TIMERS
 
 config SOUND_SH_DAC_AUDIO_CHANNEL
 	int "DAC channel"