drm/amdgpu: Remove a few holes from struct amdgpu_ctx

drm/amdgpu: Remove a few holes from struct amdgpu_ctx

Re-order the struct members a bit to avoid some holes:

 /* size: 408, cachelines: 7, members: 15 */
 /* sum members: 393, holes: 4, sum holes: 15 */
 /* last cacheline: 24 bytes */

 /* size: 400, cachelines: 7, members: 15 */
 /* sum members: 393, holes: 1, sum holes: 7 */
 /* last cacheline: 16 bytes */

While doing so we notice a duplicate but will address than in the
following patch.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>