staging: rtl8192u: use __packed instead of __attribute__((packed))

This patch fixes the following checkpatch warning:
WARNING: __packed is preferred over __attribute__((packed))

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/rtl8192u/r819xU_phy.h b/drivers/staging/rtl8192u/r819xU_phy.h
index f3c352a..66cbe3f 100644
--- a/drivers/staging/rtl8192u/r819xU_phy.h
+++ b/drivers/staging/rtl8192u/r819xU_phy.h
@@ -23,7 +23,7 @@
 	u32		Para1;
 	u32		Para2;
 	u32		msDelay;
-} __attribute__ ((packed)) SwChnlCmd;
+} __packed SwChnlCmd;
 
 extern u32 rtl819XMACPHY_Array_PG[];
 extern u32 rtl819XPHY_REG_1T2RArray[];