Rename __attribute__((packed)) --> __packed

Also unify __attribute__ ((..)) to __attribute__((..)) and
handle ((__packed__)) like ((packed))

Change-Id: Ie60a51c3fa92b5009724a5b7c2932e361bf3490c
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-on: https://review.coreboot.org/15921
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

util/cbfstool/linux.h

@@ -89,7 +89,7 @@ struct linux_header {
 	/* 2.10+ */
 	u64 pref_address;	/* 0x258 */
 	u32 init_size;		/* 0x260 */
-} __attribute__ ((packed));
+} __packed;
 
 /* Paramters passed to 32-bit part of Linux
  * This is another view of the structure above.. */