drm/armada: fix YUV planar format framebuffer offsets

We weren't correctly calculating the YUV planar offsets for subsampled
chroma planes correctly - fix up the coordinates for planes 1 and 2.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

drivers/gpu/drm/armada/armada_crtc.c

@@ -176,7 +176,13 @@ void armada_drm_plane_calc_addrs(u32 *addrs, struct drm_framebuffer *fb,
 	if (num_planes > 3)
 		num_planes = 3;
 
-	for (i = 0; i < num_planes; i++)
+	addrs[0] = addr + fb->offsets[0] + y * fb->pitches[0] +
+		   x * format->cpp[0];
+
+	y /= format->vsub;
+	x /= format->hsub;
+
+	for (i = 1; i < num_planes; i++)
 		addrs[i] = addr + fb->offsets[i] + y * fb->pitches[i] +
 			     x * format->cpp[i];
 	for (; i < 3; i++)