drm: adp: Use spin_lock_irqsave for drm device event_lock

The lock is used in the interrupt handler so use spin_lock_irqsave to
disable interrupts and avoid deadlocks with the irq handler.

Fixes: 332122e ("drm: adp: Add Apple Display Pipe driver")
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Janne Grunau <j@jannau.net>
Link: https://lore.kernel.org/r/20250428-drm_adp_fixes-v2-1-912e081e55d8@jannau.net
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>

Author: jannau

drivers/gpu/drm/adp/adp_drv.c

@@ -310,6 +310,7 @@ static void adp_crtc_atomic_flush(struct drm_crtc *crtc,
 				  struct drm_atomic_state *state)
 {
 	u32 frame_num = 1;
+	unsigned long flags;
 	struct adp_drv_private *adp = crtc_to_adp(crtc);
 	struct drm_crtc_state *new_state = drm_atomic_get_new_crtc_state(state, crtc);
 	u64 new_size = ALIGN(new_state->mode.hdisplay *
@@ -330,13 +331,13 @@ static void adp_crtc_atomic_flush(struct drm_crtc *crtc,
 	}
 	writel(ADBE_FIFO_SYNC | frame_num, adp->be + ADBE_FIFO);
 	//FIXME: use adbe flush interrupt
-	spin_lock_irq(&crtc->dev->event_lock);
+	spin_lock_irqsave(&crtc->dev->event_lock, flags);
 	if (crtc->state->event) {
 		drm_crtc_vblank_get(crtc);
 		adp->event = crtc->state->event;
 	}
 	crtc->state->event = NULL;
-	spin_unlock_irq(&crtc->dev->event_lock);
+	spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
 }
 
 static const struct drm_crtc_funcs adp_crtc_funcs = {