drm/amdgpu: Fix a a typo in a comment

s/than/then/
Acked-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c

@@ -662,7 +662,7 @@ static int amdgpu_cs_sync_rings(struct amdgpu_cs_parser *p)
  * @error:	error number
  * @backoff:	indicator to backoff the reservation
  *
- * If error is set than unvalidate buffer, otherwise just free memory
+ * If error is set then unvalidate buffer, otherwise just free memory
  * used by parsing context.
  **/
 static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser, int error,