block: Use macros from compiler.h instead of __attribute__((...))

To increase compiler portability there are several macros defined
in <linux/compiler.h> for various gcc __attribute((..)) constructs.
I've made sure gcc these specific were replaced with the right
macro and an #include <linux/compiler.h> was placed where needed.

Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/partitions/atari.h b/block/partitions/atari.h
index fe2d32a..f2ec43b 100644
--- a/block/partitions/atari.h
+++ b/block/partitions/atari.h
@@ -11,6 +11,8 @@
  * by Guenther Kelleter (guenther@pool.informatik.rwth-aachen.de)
  */
 
+#include <linux/compiler.h>
+
 struct partition_info
 {
   u8 flg;			/* bit 0: active; bit 7: bootable */
@@ -29,6 +31,6 @@
   u32 bsl_st;			/* start of bad sector list */
   u32 bsl_cnt;			/* length of bad sector list */
   u16 checksum;			/* checksum for bootable disks */
-} __attribute__((__packed__));
+} __packed;
 
 int atari_partition(struct parsed_partitions *state);