ioctl: Rearrange members in nvme_get_features_args

ioctl: Rearrange members in nvme_get_features_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_get_features_args {
        int                        args_size;            /*     0     4 */
        int                        fd;                   /*     4     4 */
        __u32 *                    result;               /*     8     8 */
        __u32                      timeout;              /*    16     4 */
        __u32                      nsid;                 /*    20     4 */
        enum nvme_get_features_sel sel;                  /*    24     4 */
        __u32                      cdw11;                /*    28     4 */
        __u32                      data_len;             /*    32     4 */
        void *                     data;                 /*    36     8 */
        __u8                       fid;                  /*    44     1 */
        __u8                       uuidx;                /*    45     1 */

        /* size: 48, cachelines: 1, members: 11 */
        /* padding: 2 */
        /* last cacheline: 48 bytes */
} __attribute__((__aligned__(8)));

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