[NET]: Introduce and use print_mac() and DECLARE_MAC_BUF()

This is nicer than the MAC_FMT stuff.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c
index 8ceda33..9efb84c 100644
--- a/net/mac80211/debugfs_netdev.c
+++ b/net/mac80211/debugfs_netdev.c
@@ -66,7 +66,8 @@
 	const struct ieee80211_sub_if_data *sdata, char *buf,		\
 	int buflen)							\
 {									\
-	return scnprintf(buf, buflen, MAC_FMT "\n", MAC_ARG(sdata->field));\
+	DECLARE_MAC_BUF(mac);						\
+	return scnprintf(buf, buflen, "%s\n", print_mac(mac, sdata->field));\
 }
 
 #define __IEEE80211_IF_FILE(name)					\