drm/i915: Split the ringbuffers from the rings (2/3)

This refactoring has been performed using the following Coccinelle
semantic script:

    @@
    struct intel_engine_cs r;
    @@
    (
    - (r).obj
    + r.buffer->obj
    |
    - (r).virtual_start
    + r.buffer->virtual_start
    |
    - (r).head
    + r.buffer->head
    |
    - (r).tail
    + r.buffer->tail
    |
    - (r).space
    + r.buffer->space
    |
    - (r).size
    + r.buffer->size
    |
    - (r).effective_size
    + r.buffer->effective_size
    |
    - (r).last_retired_head
    + r.buffer->last_retired_head
    )

    @@
    struct intel_engine_cs *r;
    @@
    (
    - (r)->obj
    + r->buffer->obj
    |
    - (r)->virtual_start
    + r->buffer->virtual_start
    |
    - (r)->head
    + r->buffer->head
    |
    - (r)->tail
    + r->buffer->tail
    |
    - (r)->space
    + r->buffer->space
    |
    - (r)->size
    + r->buffer->size
    |
    - (r)->effective_size
    + r->buffer->effective_size
    |
    - (r)->last_retired_head
    + r->buffer->last_retired_head
    )

    @@
    expression E;
    @@
    (
    - LP_RING(E)->obj
    + LP_RING(E)->buffer->obj
    |
    - LP_RING(E)->virtual_start
    + LP_RING(E)->buffer->virtual_start
    |
    - LP_RING(E)->head
    + LP_RING(E)->buffer->head
    |
    - LP_RING(E)->tail
    + LP_RING(E)->buffer->tail
    |
    - LP_RING(E)->space
    + LP_RING(E)->buffer->space
    |
    - LP_RING(E)->size
    + LP_RING(E)->buffer->size
    |
    - LP_RING(E)->effective_size
    + LP_RING(E)->buffer->effective_size
    |
    - LP_RING(E)->last_retired_head
    + LP_RING(E)->buffer->last_retired_head
    )

Note: On top of this this patch also removes the now unused ringbuffer
fields in intel_engine_cs.

Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
[danvet: Add note about fixup patch included here.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index c28e0da..152ba12 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1219,7 +1219,7 @@
 static void notify_ring(struct drm_device *dev,
 			struct intel_engine_cs *ring)
 {
-	if (ring->obj == NULL)
+	if (ring->buffer->obj == NULL)
 		return;
 
 	trace_i915_gem_request_complete(ring);
@@ -2837,10 +2837,10 @@
 		 * our ring is smaller than what the hardware (and hence
 		 * HEAD_ADDR) allows. Also handles wrap-around.
 		 */
-		head &= ring->size - 1;
+		head &= ring->buffer->size - 1;
 
 		/* This here seems to blow up */
-		cmd = ioread32(ring->virtual_start + head);
+		cmd = ioread32(ring->buffer->virtual_start + head);
 		if (cmd == ipehr)
 			break;
 
@@ -2850,7 +2850,7 @@
 	if (!i)
 		return NULL;
 
-	*seqno = ioread32(ring->virtual_start + head + 4) + 1;
+	*seqno = ioread32(ring->buffer->virtual_start + head + 4) + 1;
 	return semaphore_wait_to_signaller_ring(ring, ipehr);
 }