ioctl: Rearrange members in nvme_capacity_mgmt_args

ioctl: Rearrange members in nvme_capacity_mgmt_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_capacity_mgmt_args {
        int                        args_size;            /*     0     4 */
        int                        fd;                   /*     4     4 */
        __u32 *                    result;               /*     8     8 */
        __u32                      timeout;              /*    16     4 */
        __u32                      cdw11;                /*    20     4 */
        __u32                      cdw12;                /*    24     4 */
        __u16                      element_id;           /*    28     2 */
        __u8                       op;                   /*    30     1 */

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

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