drm/i915: Add missing kerneldoc for 'ent' in i915_driver_init_early

drivers/gpu/drm/i915/i915_drv.c:891: warning: No description found for parameter 'ent'
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180208105449.29880-1-chris@chris-wilson.co.ukReviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/i915_drv.c

@@ -873,6 +873,7 @@ static void intel_detect_preproduction_hw(struct drm_i915_private *dev_priv)
 /**
  * i915_driver_init_early - setup state not requiring device access
  * @dev_priv: device private
+ * @ent: the matching pci_device_id
  *
  * Initialize everything that is a "SW-only" state, that is state not
  * requiring accessing the device or exposing the driver via kernel internal