nvc0: Fix index of unk fields in nve4_cp_launch_desc

Signed-off-by: Boyan Ding <boyan.j.ding@gmail.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>

src/gallium/drivers/nouveau/nvc0/nve4_compute.h

@@ -18,8 +18,8 @@ struct nve4_cp_launch_desc
    u16 griddim_z;
    u32 unk14[3];
    u16 shared_size; /* must be aligned to 0x100 */
-   u16 unk15;
-   u16 unk16;
+   u16 unk17;
+   u16 unk18;
    u16 blockdim_x;
    u16 blockdim_y;
    u16 blockdim_z;