drm/i915: Fix inconsistent indenting in i915_error_state_to_str()

smatch complains:
	drivers/gpu/drm/i915/i915_gpu_error.c:503 i915_error_state_to_str()
	warn: inconsistent indenting
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1467470166-31717-4-git-send-email-chris@chris-wilson.co.ukReviewed-by: Matthew Auld <matthew.auld@intel.com>

drivers/gpu/drm/i915/i915_gpu_error.c

@@ -500,7 +500,7 @@ int i915_error_state_to_str(struct drm_i915_error_state_buf *m,
 					   hws_page[elt+1],
 					   hws_page[elt+2],
 					   hws_page[elt+3]);
-					offset += 16;
+				offset += 16;
 			}
 		}