net: wireless: replace strict_strtoul() with kstrtoul()

The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/wireless/ath/ath9k/dfs_debug.c b/drivers/net/wireless/ath/ath9k/dfs_debug.c
index b7611b7..3c6e413 100644
--- a/drivers/net/wireless/ath/ath9k/dfs_debug.c
+++ b/drivers/net/wireless/ath/ath9k/dfs_debug.c
@@ -96,7 +96,7 @@
 		return -EFAULT;
 
 	buf[len] = '\0';
-	if (strict_strtoul(buf, 0, &val))
+	if (kstrtoul(buf, 0, &val))
 		return -EINVAL;
 
 	if (val == DFS_STATS_RESET_MAGIC)