ASoC: rt5670: Remove 'OUT Channel Switch' control

The "OUT Channel Switch" control is a left over from code copied from
thr rt5640 codec driver.

With the rt5640 codec driver the output volume controls have 2 pairs of
mute bits:
bit 7, 15: Mute Control for Spk/Headphone/Line Output Port
bit 6, 14: Mute Control for Spk/Headphone/Line Volume Channel

Bits 7 and 15 are normal mute bits on the rt5670/5672 which are
controlled by 2 dapm widgets:
	SND_SOC_DAPM_SWITCH("LOUT L Playback", SND_SOC_NOPM, 0, 0,
			    &lout_l_enable_control),
	SND_SOC_DAPM_SWITCH("LOUT R Playback", SND_SOC_NOPM, 0, 0,
			    &lout_r_enable_control),

But on the 5670/5672 bit 6 is always reserved, where as bit 14 is
"LOUT Differential Mode" on the 5670 and also reserved on the 5672.

So the "OUT Channel Switch" control which is controlling bits 6+14
of the "LINE Output Control" register is bogus -> remove it.

This should not cause any issues for userspace. AFAICT the rt567x codecs
are only used on x86/ACPI devices and the UCM profiles used there do not
use the "OUT Channel Switch" control.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210215142118.308516-2-hdegoede@redhat.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/rt5670.c

@@ -637,8 +637,6 @@ static const struct snd_kcontrol_new rt5670_snd_controls[] = {
 		RT5670_L_VOL_SFT, RT5670_R_VOL_SFT,
 		39, 1, out_vol_tlv),
 	/* OUTPUT Control */
-	SOC_DOUBLE("OUT Channel Switch", RT5670_LOUT1,
-		RT5670_VOL_L_SFT, RT5670_VOL_R_SFT, 1, 1),
 	SOC_DOUBLE_TLV("OUT Playback Volume", RT5670_LOUT1,
 		RT5670_L_VOL_SFT, RT5670_R_VOL_SFT, 39, 1, out_vol_tlv),
 	/* DAC Digital Volume */

sound/soc/codecs/rt5670.h

@@ -212,12 +212,8 @@
 /* global definition */
 #define RT5670_L_MUTE				(0x1 << 15)
 #define RT5670_L_MUTE_SFT			15
-#define RT5670_VOL_L_MUTE			(0x1 << 14)
-#define RT5670_VOL_L_SFT			14
 #define RT5670_R_MUTE				(0x1 << 7)
 #define RT5670_R_MUTE_SFT			7
-#define RT5670_VOL_R_MUTE			(0x1 << 6)
-#define RT5670_VOL_R_SFT			6
 #define RT5670_L_VOL_MASK			(0x3f << 8)
 #define RT5670_L_VOL_SFT			8
 #define RT5670_R_VOL_MASK			(0x3f)