staging: wilc1000: linux_mon: use __packed instead of __attribute__((packed))

This patch fixes the following checkpatch warning:
WARNING: __packed is preferred over __attribute__((packed))
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wilc1000/linux_mon.c

@@ -15,14 +15,14 @@
 struct wilc_wfi_radiotap_hdr {
 	struct ieee80211_radiotap_header hdr;
 	u8 rate;
-} __attribute__((packed));
+} __packed;
 
 struct wilc_wfi_radiotap_cb_hdr {
 	struct ieee80211_radiotap_header hdr;
 	u8 rate;
 	u8 dump;
 	u16 tx_flags;
-} __attribute__((packed));
+} __packed;
 
 static struct net_device *wilc_wfi_mon; /* global monitor netdev */