drm/radeon: use pflip irq on R600+ v2

Testing the update pending bit directly after issuing an
update is nonsense cause depending on the pixel clock the
CRTC needs a bit of time to execute the flip even when we
are in the VBLANK period.

This is just a non invasive patch to solve the problem at
hand, a more complete and cleaner solution should follow
in the next merge window.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=76564

v2: fix source IDs for CRTC2-6

Signed-off-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index b58e1af..6852861 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -730,6 +730,12 @@
 	u32 disp_int_cont4;
 	u32 disp_int_cont5;
 	u32 disp_int_cont6;
+	u32 d1grph_int;
+	u32 d2grph_int;
+	u32 d3grph_int;
+	u32 d4grph_int;
+	u32 d5grph_int;
+	u32 d6grph_int;
 };
 
 union radeon_irq_stat_regs {