ALSA: hda - Remove EXPERIMENTAL from CONFIG_SND_HDA_POWER_SAVE

It's mature enough now.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/Kconfig

@@ -122,7 +122,6 @@ config SND_HDA_GENERIC
 
 config SND_HDA_POWER_SAVE
 	bool "Aggressive power-saving on HD-audio"
-	depends on EXPERIMENTAL
 	help
 	  Say Y here to enable more aggressive power-saving mode on
 	  HD-audio driver.  The power-saving timeout can be configured