[ALSA] Add SPI devices to ALSA Kconfig and Makefile

This patch adds SPI devices in the ALSA diretory, including the Kconfig and
Makefile.

Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/Kconfig

@@ -63,6 +63,10 @@ source "sound/aoa/Kconfig"
 
 source "sound/arm/Kconfig"
 
+if SPI
+source "sound/spi/Kconfig"
+endif
+
 source "sound/mips/Kconfig"
 
 source "sound/sh/Kconfig"