Staging: line6: depends on SND

line6 code has lots of dependencies on ALSA (and build errors),
so express that in Kconfig.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Markus Grabner <grabner@icg.tugraz.at>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/line6/Kconfig

 config LINE6_USB
 	tristate "Line6 USB support"
-	depends on USB
+	depends on USB && SND
 	help
 	  This is a driver for the guitar amp, cab, and effects modeller
 	  PODxt Pro by Line6 (and similar devices), supporting the