drm/radeon/kms: add wait_for_vblank asic callback

Required for future functionality.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 884e0d4..e19a430 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -1204,6 +1204,8 @@
 	void (*pre_page_flip)(struct radeon_device *rdev, int crtc);
 	u32 (*page_flip)(struct radeon_device *rdev, int crtc, u64 crtc_base);
 	void (*post_page_flip)(struct radeon_device *rdev, int crtc);
+	/* wait for vblank */
+	void (*wait_for_vblank)(struct radeon_device *rdev, int crtc);
 };
 
 /*
@@ -1692,6 +1694,7 @@
 #define radeon_pre_page_flip(rdev, crtc) rdev->asic->pre_page_flip((rdev), (crtc))
 #define radeon_page_flip(rdev, crtc, base) rdev->asic->page_flip((rdev), (crtc), (base))
 #define radeon_post_page_flip(rdev, crtc) rdev->asic->post_page_flip((rdev), (crtc))
+#define radeon_wait_for_vblank(rdev, crtc) rdev->asic->wait_for_vblank((rdev), (crtc))
 
 /* Common functions */
 /* AGP */