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>

src/vboot/vboot_common.h

@@ -17,6 +17,7 @@
 
 #include <commonlib/region.h>
 #include <stdint.h>
+#include <compiler.h>
 #include <vboot_api.h>
 #include <vboot_struct.h>
 
@@ -42,7 +43,7 @@ struct vboot_handoff {
 	VbInitParams init_params;
 	uint32_t selected_firmware;
 	char shared_data[VB_SHARED_DATA_MIN_SIZE];
-} __attribute__((packed));
+} __packed;
 
 /*
  * vboot_get_handoff_info returns pointer to the vboot_handoff structure if