drm/i915: Drop the shadow ring state from the error capture

The shadow ring regs (ring->head, ring->tail) are meaningless in the
post-mortem dump as they do not related to anything on HW. Remove them
from the coredump.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200110123059.1348712-3-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -553,8 +553,6 @@ static void error_print_engine(struct drm_i915_error_state_buf *m,
 				   ee->vm_info.pp_dir_base);
 		}
 	}
-	err_printf(m, "  ring->head: 0x%08x\n", ee->cpu_ring_head);
-	err_printf(m, "  ring->tail: 0x%08x\n", ee->cpu_ring_tail);
 	err_printf(m, "  engine reset count: %u\n", ee->reset_count);
 
 	for (n = 0; n < ee->num_ports; n++) {
@@ -1429,9 +1427,6 @@ intel_engine_coredump_add_request(struct intel_engine_coredump *ee,
 	vma = capture_vma(vma, rq->ring->vma, "ring", gfp);
 	vma = capture_vma(vma, rq->context->state, "HW context", gfp);
 
-	ee->cpu_ring_head = rq->ring->head;
-	ee->cpu_ring_tail = rq->ring->tail;
-
 	ee->rq_head = rq->head;
 	ee->rq_post = rq->postfix;
 	ee->rq_tail = rq->tail;

drivers/gpu/drm/i915/i915_gpu_error.h

@@ -66,10 +66,6 @@ struct intel_engine_coredump {
 	/* position of active request inside the ring */
 	u32 rq_head, rq_post, rq_tail;
 
-	/* our own tracking of ring head and tail */
-	u32 cpu_ring_head;
-	u32 cpu_ring_tail;
-
 	/* Register state */
 	u32 ccid;
 	u32 start;