rt2x00: Fix Sparse warning

rt2x00link_reset_qual() is not declared in a header,
and is only internally used within rt2x00link.c.
It should be declared as static.

Signed-off-by: Ivo van Doorn <[e-mail]>
Signed-off-by: John W. Linville <[e-mail]>

drivers/net/wireless/rt2x00/rt2x00link.c

···
 		rt2x00link_antenna_reset(rt2x00dev);
 }
 
-void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev)
+static void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev)
 {
 	struct link_qual *qual = &rt2x00dev->link.qual;