ALSA: line6: toneport: Use explicit type for firmware version

The firmware version is a single byte so have the variable type agree.
Since the address to this member is passed to the read function, using
an int is not even portable.
Signed-off-by: NChris Rorvick <chris@rorvick.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/usb/line6/toneport.c

@@ -52,7 +52,7 @@ struct usb_line6_toneport {
 	u32 serial_number;
 
 	/* Firmware version (x 100) */
-	int firmware_version;
+	u8 firmware_version;
 
 	/* Timer for delayed PCM startup */
 	struct timer_list timer;