drm/radeon: fix count in cik_sdma_ring_test()

Should be 5 rather than 4.
Noticed-by: Mathias Fröhlich <Mathias.Froehlich@gmx.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christian König <christian.koenig@amd.com>

drivers/gpu/drm/radeon/cik_sdma.c

@@ -597,7 +597,7 @@ int cik_sdma_ring_test(struct radeon_device *rdev,
 	tmp = 0xCAFEDEAD;
 	writel(tmp, ptr);
 
-	r = radeon_ring_lock(rdev, ring, 4);
+	r = radeon_ring_lock(rdev, ring, 5);
 	if (r) {
 		DRM_ERROR("radeon: dma failed to lock ring %d (%d).\n", ring->idx, r);
 		return r;