sound: Make keywest_driver static

I can't see any reason for struct i2c_driver keywest_driver to not be
static.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/ppc/keywest.c b/sound/ppc/keywest.c
index bb6819a..d06f780 100644
--- a/sound/ppc/keywest.c
+++ b/sound/ppc/keywest.c
@@ -98,7 +98,7 @@
 	{ }
 };
 
-struct i2c_driver keywest_driver = {
+static struct i2c_driver keywest_driver = {
 	.driver = {
 		.name = "PMac Keywest Audio",
 	},