switch debugfs to umode_t

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/net/wireless/ath/carl9170/debug.c b/drivers/net/wireless/ath/carl9170/debug.c
index de57f90..3c16422 100644
--- a/drivers/net/wireless/ath/carl9170/debug.c
+++ b/drivers/net/wireless/ath/carl9170/debug.c
@@ -56,7 +56,7 @@
 
 struct carl9170_debugfs_fops {
 	unsigned int read_bufsize;
-	mode_t attr;
+	umode_t attr;
 	char *(*read)(struct ar9170 *ar, char *buf, size_t bufsize,
 		      ssize_t *len);
 	ssize_t (*write)(struct ar9170 *aru, const char *buf, size_t size);