drm/doc: Switch to sphinx/rst fixed-width quoting

Just fallout from switching from asciidoc to sphinx/rst.

v2: Found more. Also s/\//#/ in the vgpu ascii-art - sphinx treats
those as comments and switch to variable-width, which wreaks the
layout.

v3: Undo some of the hacks, rebasing onto latest version of Jani's
series fixed it.

Acked-by: Liviu Dudau <Liviu.Dudau@arm.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c
index d5a7a5e..0043262 100644
--- a/drivers/gpu/drm/i915/i915_vgpu.c
+++ b/drivers/gpu/drm/i915/i915_vgpu.c
@@ -150,28 +150,28 @@
  * of its graphic space being zero. Yet there are some portions ballooned out(
  * the shadow part, which are marked as reserved by drm allocator). From the
  * host point of view, the graphic address space is partitioned by multiple
- * vGPUs in different VMs.
+ * vGPUs in different VMs. ::
  *
  *                        vGPU1 view         Host view
  *             0 ------> +-----------+     +-----------+
- *               ^       |///////////|     |   vGPU3   |
- *               |       |///////////|     +-----------+
- *               |       |///////////|     |   vGPU2   |
+ *               ^       |###########|     |   vGPU3   |
+ *               |       |###########|     +-----------+
+ *               |       |###########|     |   vGPU2   |
  *               |       +-----------+     +-----------+
  *        mappable GM    | available | ==> |   vGPU1   |
  *               |       +-----------+     +-----------+
- *               |       |///////////|     |           |
- *               v       |///////////|     |   Host    |
+ *               |       |###########|     |           |
+ *               v       |###########|     |   Host    |
  *               +=======+===========+     +===========+
- *               ^       |///////////|     |   vGPU3   |
- *               |       |///////////|     +-----------+
- *               |       |///////////|     |   vGPU2   |
+ *               ^       |###########|     |   vGPU3   |
+ *               |       |###########|     +-----------+
+ *               |       |###########|     |   vGPU2   |
  *               |       +-----------+     +-----------+
  *      unmappable GM    | available | ==> |   vGPU1   |
  *               |       +-----------+     +-----------+
- *               |       |///////////|     |           |
- *               |       |///////////|     |   Host    |
- *               v       |///////////|     |           |
+ *               |       |###########|     |           |
+ *               |       |###########|     |   Host    |
+ *               v       |###########|     |           |
  * total GM size ------> +-----------+     +-----------+
  *
  * Returns: