mtd: nand: use __packed shorthand

To be consistent with the rest of include/linux/mtd/nand.h, we should
use the __packed shorthand instead of __attribute__((packed)).
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Huang Shijie <b32955@freescale.com>

include/linux/mtd/nand.h

@@ -292,7 +292,7 @@ struct nand_onfi_params {
 	u8 vendor[88];
 
 	__le16 crc;
-} __attribute__((packed));
+} __packed;
 
 #define ONFI_CRC_BASE	0x4F4E