ioctl: Rearrange members in nvme_directive_recv_args

ioctl: Rearrange members in nvme_directive_recv_args

Avoid any holes in the struct by rearranging the members. Also add the
attribute packed to struct definition to reduce ABI breakage.

struct nvme_directive_recv_args {
        int                        args_size;            /*     0     4 */
        int                        fd;                   /*     4     4 */
        __u32 *                    result;               /*     8     8 */
        __u32                      timeout;              /*    16     4 */
        __u32                      nsid;                 /*    20     4 */
        enum nvme_directive_receive_doper doper;         /*    24     4 */
        enum nvme_directive_dtype  dtype;                /*    28     4 */
        __u32                      cdw12;                /*    32     4 */
        __u32                      data_len;             /*    36     4 */
        void *                     data;                 /*    40     8 */
        __u16                      dspec;                /*    48     2 */

        /* size: 56, cachelines: 1, members: 11 */
        /* padding: 6 */
        /* last cacheline: 56 bytes */
} __attribute__((__aligned__(8)));

Signed-off-by: Daniel Wagner <dwagner@suse.de>