drm/lima: Make lima_sched_ops static

Fix sparse warning:

drivers/gpu/drm/lima/lima_sched.c:356:36: warning:
symbol 'lima_sched_ops' was not declared. Should it be static?

Fixes: a1d2a6339961 ("drm/lima: driver for ARM Mali4xx GPUs")
Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: YueHaibing <[e-mail]>
Signed-off-by: Qiang Yu <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/lima/lima_sched.c

···
 	kmem_cache_free(pipe->task_slab, task);
 }
 
-const struct drm_sched_backend_ops lima_sched_ops = {
+static const struct drm_sched_backend_ops lima_sched_ops = {
 	.dependency = lima_sched_dependency,
 	.run_job = lima_sched_run_job,
 	.timedout_job = lima_sched_timedout_job,