drm/i915/gem: Use local pointer ttm for __i915_ttm_move

Using local pointer ttm as argument in  __i915_ttm_move instead of bo->ttm,
as local pointer was previously assigned to bo->ttm in function.
This will make code a bit more readable.
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Jasmine Newsome <jasmine.newsome@intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220104203642.231878-1-jasmine.newsome@intel.com

drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c

@@ -525,7 +525,7 @@ int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
 			return ret;
 		}
 
-		migration_fence = __i915_ttm_move(bo, ctx, clear, dst_mem, bo->ttm,
+		migration_fence = __i915_ttm_move(bo, ctx, clear, dst_mem, ttm,
 						  dst_rsgt, true, &deps);
 		i915_deps_fini(&deps);
 	}