drm/radeon/dce6: add missing display reg for tiling setup

A new tiling config register for the display blocks was
added on DCE6.

May fix:
https://bugs.freedesktop.org/show_bug.cgi?id=62889
https://bugs.freedesktop.org/show_bug.cgi?id=57919

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/nid.h b/drivers/gpu/drm/radeon/nid.h
index 079dee2..445b235 100644
--- a/drivers/gpu/drm/radeon/nid.h
+++ b/drivers/gpu/drm/radeon/nid.h
@@ -45,6 +45,10 @@
 #define ARUBA_GB_ADDR_CONFIG_GOLDEN        0x12010001
 
 #define DMIF_ADDR_CONFIG  				0xBD4
+
+/* DCE6 only */
+#define DMIF_ADDR_CALC  				0xC00
+
 #define	SRBM_GFX_CNTL				        0x0E44
 #define		RINGID(x)					(((x) & 0x3) << 0)
 #define		VMID(x)						(((x) & 0x7) << 0)