ath9k: drop negativity checks for unsigned values coming from kstrtoul()

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=80471
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=80481
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Andrey Utkin <andrey.krieger.utkin@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/debug.c b/drivers/net/wireless/ath/ath9k/debug.c
index ce073e9..d227936 100644
--- a/drivers/net/wireless/ath/ath9k/debug.c
+++ b/drivers/net/wireless/ath/ath9k/debug.c
@@ -202,7 +202,7 @@
 	if (kstrtoul(buf, 0, &ani))
 		return -EINVAL;
 
-	if (ani < 0 || ani > 1)
+	if (ani > 1)
 		return -EINVAL;
 
 	common->disable_ani = !ani;