drm/vc4: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Eric Anholt <eric@anholt.net>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20171024151648.GA104538@beast
Reviewed-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/vc4/vc4_gem.c

@@ -312,10 +312,10 @@ vc4_reset_work(struct work_struct *work)
 }
 
 static void
-vc4_hangcheck_elapsed(unsigned long data)
+vc4_hangcheck_elapsed(struct timer_list *t)
 {
-	struct drm_device *dev = (struct drm_device *)data;
-	struct vc4_dev *vc4 = to_vc4_dev(dev);
+	struct vc4_dev *vc4 = from_timer(vc4, t, hangcheck.timer);
+	struct drm_device *dev = vc4->dev;
 	uint32_t ct0ca, ct1ca;
 	unsigned long irqflags;
 	struct vc4_exec_info *bin_exec, *render_exec;
@@ -1154,9 +1154,7 @@ vc4_gem_init(struct drm_device *dev)
 	spin_lock_init(&vc4->job_lock);
 
 	INIT_WORK(&vc4->hangcheck.reset_work, vc4_reset_work);
-	setup_timer(&vc4->hangcheck.timer,
-		    vc4_hangcheck_elapsed,
-		    (unsigned long)dev);
+	timer_setup(&vc4->hangcheck.timer, vc4_hangcheck_elapsed, 0);
 
 	INIT_WORK(&vc4->job_done_work, vc4_job_done_work);