[ALSA] emu10k1 - Fix inverted Analog/Digital mixer switch on Audigy2

On Audigy2 Platinum, the Analog/Digital mixer switch is inverted.
	https://bugzilla.novell.com/show_bug.cgi?id=396204

The patch adds a simple workaround.

There might be another device requiring a similar fix, too (or fix for
audigy2 generically), but right now I fix only the known broken one.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/emu10k1.h

@@ -1670,6 +1670,7 @@ struct snd_emu_chip_details {
 	unsigned char spi_dac;      /* SPI interface for DAC */
 	unsigned char i2c_adc;      /* I2C interface for ADC */
 	unsigned char adc_1361t;    /* Use Philips 1361T ADC */
+	unsigned char invert_shared_spdif; /* analog/digital switch inverted */
 	const char *driver;
 	const char *name;
 	const char *id;		/* for backward compatibility - can be NULL if not needed */