drm/i915: Enable refcount debugging for default debug levels

refcount_t is our first line of defence against use-after-free, so let's
enable it for debugging.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613122842.4840-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/Kconfig.debug

@@ -21,6 +21,7 @@ config DRM_I915_DEBUG
         depends on DRM_I915
         select DEBUG_FS
         select PREEMPT_COUNT
+        select REFCOUNT_FULL
         select I2C_CHARDEV
         select STACKDEPOT
         select DRM_DP_AUX_CHARDEV