RDMA: Use __packed annotation instead of __attribute__ ((packed))

"__attribute__" set of macros has been standardized, have became more
potentially portable and consistent code back in v2.6.21 by commit
82ddcb040 ("[PATCH] extend the set of "__attribute__" shortcut macros").
Moreover, nowadays checkpatch.pl warns about using __attribute__((packed))
instead of __packed.

This patch converts all the "__attribute__ ((packed))" annotations to
"__packed" within the RDMA subsystem.

Signed-off-by: Erez Alfasi <ereza@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mthca/mthca_mr.c

@@ -60,7 +60,7 @@ struct mthca_mpt_entry {
 	__be64 mtt_seg;
 	__be32 mtt_sz;		/* Arbel only */
 	u32    reserved[2];
-} __attribute__((packed));
+} __packed;
 
 #define MTHCA_MPT_FLAG_SW_OWNS       (0xfUL << 28)
 #define MTHCA_MPT_FLAG_MIO           (1 << 17)