drm/i915: Actually capture PP_DIR_BASE on error

I have been seeing this for a long time, but ignored it because it's
typically not terribly important. Recently, I really needed this info,
and it was garbage. Proof that I should have fixed it sooner. Originally
wrong from:

commit 6c7a01ec
Author: Ben Widawsky <benjamin.widawsky@intel.com>
Date:   Thu Jan 30 00:19:40 2014 -0800

    drm/i915: Capture PPGTT info on error capture

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -850,10 +850,12 @@ static void i915_record_ring_state(struct drm_device *dev,
 			}
 			break;
 		case 7:
-			ering->vm_info.pp_dir_base = RING_PP_DIR_BASE(ring);
+			ering->vm_info.pp_dir_base =
+				I915_READ(RING_PP_DIR_BASE(ring));
 			break;
 		case 6:
-			ering->vm_info.pp_dir_base = RING_PP_DIR_BASE_READ(ring);
+			ering->vm_info.pp_dir_base =
+				I915_READ(RING_PP_DIR_BASE_READ(ring));
 			break;
 		}
 	}