drm/gma500: use drm_modeset_lock_all

Only two places:
- suspend/resume
- Some really strange mode validation tool with too much funny-lucking
  hand-rolled conversion code.
- The recently-added lastclose fbdev restore code.

Better safe than sorry, so convert both places to keep the locking
semantics as much as possible.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/gma500/psb_device.c b/drivers/gpu/drm/gma500/psb_device.c
index b58c470..f6f534b 100644
--- a/drivers/gpu/drm/gma500/psb_device.c
+++ b/drivers/gpu/drm/gma500/psb_device.c
@@ -194,7 +194,7 @@
 	regs->saveCHICKENBIT = PSB_RVDC32(DSPCHICKENBIT);
 
 	/* Save crtc and output state */
-	mutex_lock(&dev->mode_config.mutex);
+	drm_modeset_lock_all(dev);
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 		if (drm_helper_crtc_in_use(crtc))
 			crtc->funcs->save(crtc);
@@ -204,7 +204,7 @@
 		if (connector->funcs->save)
 			connector->funcs->save(connector);
 
-	mutex_unlock(&dev->mode_config.mutex);
+	drm_modeset_unlock_all(dev);
 	return 0;
 }
 
@@ -234,7 +234,7 @@
 	/*make sure VGA plane is off. it initializes to on after reset!*/
 	PSB_WVDC32(0x80000000, VGACNTRL);
 
-	mutex_lock(&dev->mode_config.mutex);
+	drm_modeset_lock_all(dev);
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
 		if (drm_helper_crtc_in_use(crtc))
 			crtc->funcs->restore(crtc);
@@ -243,7 +243,7 @@
 		if (connector->funcs->restore)
 			connector->funcs->restore(connector);
 
-	mutex_unlock(&dev->mode_config.mutex);
+	drm_modeset_unlock_all(dev);
 	return 0;
 }